CVE-2019-11479

Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.

From the Ubuntu Security Team

Jonathan Looney discovered that the Linux kernel could be coerced into segmenting responses into multiple TCP segments. A remote attacker could construct an ongoing sequence of requests to cause a denial of service.

Read the notes from the security team

Mitigation

This can be mitigated by dropping all packets which specify a too small MSS value. For example, to only allow MSS values of greater than 500 bytes, an iptables rule can be specified as: sudo iptables -A INPUT -p tcp -m tcpmss --mss 1:500 -j DROP Note: this will only take effect if the net.ipv4.tcp_mtu_probing sysctl is disabled as well.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
linux	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Not affected
	19.04 disco	Fixed 5.0.0-20.21
	18.10 cosmic	Fixed 4.18.0-25.26
	18.04 LTS bionic	Fixed 4.15.0-54.58
	16.04 LTS xenial	Fixed 4.4.0-154.181
	14.04 LTS trusty	Ignored ESM criteria, was needed
linux-aws	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Not affected
	19.04 disco	Fixed 5.0.0-1010.11
	18.10 cosmic	Fixed 4.18.0-1020.24
	18.04 LTS bionic	Fixed 4.15.0-1043.45
	16.04 LTS xenial	Fixed 4.4.0-1087.98
	14.04 LTS trusty	Not affected
linux-aws-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-aws-5.4	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-aws-6.8	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-aws-fips	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy FIPS Updates	Not affected
	20.04 LTS focal FIPS Updates	Not affected
	18.04 LTS bionic FIPS Updates	Not affected
	16.04 LTS xenial FIPS Updates	Not in release
	14.04 LTS trusty	Not in release
linux-aws-hwe	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Fixed 4.15.0-1043.45~16.04.1
	14.04 LTS trusty	Not in release
linux-azure	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Not affected
	19.04 disco	Fixed 5.0.0-1010.10
	18.10 cosmic	Fixed 4.18.0-1023.24
	18.04 LTS bionic	Fixed 4.18.0-1023.24~18.04.1
	16.04 LTS xenial	Fixed 4.15.0-1049.54
	14.04 LTS trusty	Not affected
linux-azure-4.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-azure-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-azure-5.4	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-azure-6.11	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-azure-6.8	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-azure-edge	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Fixed 4.18.0-1023.24~18.04.1
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-azure-fde	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Ignored superseded by linux-azure-fde-5.15
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-azure-fde-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-azure-fips	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy FIPS Updates	Not affected
	20.04 LTS focal FIPS Updates	Not affected
	18.04 LTS bionic FIPS Updates	Not affected
	16.04 LTS xenial FIPS Updates	Not in release
	14.04 LTS trusty	Not in release
linux-azure-nvidia	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-bluefield	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-euclid	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Ignored end of standard support, was needed
	14.04 LTS trusty	Not in release
linux-fips	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy FIPS Updates	Not affected
	20.04 LTS focal FIPS Updates	Not affected
	18.04 LTS bionic FIPS Updates	Not affected
	16.04 LTS xenial FIPS	Fixed 4.4.0-1017.22~recert1
	14.04 LTS trusty	Not in release
linux-flo	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Ignored end of standard support
	14.04 LTS trusty	Not in release
linux-gcp	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Not affected
	19.04 disco	Fixed 5.0.0-1010.10
	18.10 cosmic	Fixed 4.18.0-1015.16
	18.04 LTS bionic	Fixed 4.15.0-1036.38
	16.04 LTS xenial	Fixed 4.15.0-1036.38~16.04.1
	14.04 LTS trusty	Not in release
linux-gcp-4.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-gcp-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-gcp-5.4	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-gcp-6.8	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-gcp-edge	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Fixed 4.18.0-1015.16~18.04.1
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-gcp-fips	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy FIPS Updates	Not affected
	20.04 LTS focal FIPS Updates	Not affected
	18.04 LTS bionic FIPS Updates	Not affected
	16.04 LTS xenial FIPS Updates	Not in release
	14.04 LTS trusty	Not in release
linux-gke	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Ignored end of kernel support
	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Ignored end of standard support
	14.04 LTS trusty	Not in release
linux-gke-4.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.04 LTS bionic	Fixed 4.15.0-1036.38
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-gke-5.0	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-gkeop	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-gkeop-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-goldfish	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Ignored end of standard support
	14.04 LTS trusty	Not in release
linux-hwe	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Fixed 4.18.0-25.26~18.04.1
	16.04 LTS xenial	Fixed 4.15.0-54.58~16.04.1
	14.04 LTS trusty	Not in release
linux-hwe-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-hwe-5.4	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-hwe-6.11	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-hwe-6.8	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-hwe-edge	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Fixed 5.0.0-20.21~18.04.1
	16.04 LTS xenial	Fixed 4.15.0-54.58~16.04.1
	14.04 LTS trusty	Not in release
linux-ibm	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-ibm-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-ibm-5.4	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-intel	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-intel-iot-realtime	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-intel-iotg	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-intel-iotg-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-iot	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-kvm	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Not affected
	19.04 disco	Fixed 5.0.0-1010.11
	18.10 cosmic	Fixed 4.18.0-1016.17
	18.04 LTS bionic	Fixed 4.15.0-1038.38
	16.04 LTS xenial	Fixed 4.4.0-1051.58
	14.04 LTS trusty	Not in release
linux-lowlatency	25.04 plucky	Not in release
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-lowlatency-hwe-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-lowlatency-hwe-6.11	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-lowlatency-hwe-6.8	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-lts-trusty	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-lts-xenial	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not affected
linux-mako	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Ignored end of standard support
	14.04 LTS trusty	Not in release
linux-nvidia	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-nvidia-6.5	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-nvidia-6.8	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-nvidia-lowlatency	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-nvidia-tegra	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-nvidia-tegra-igx	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-oem	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not affected
	19.04 disco	Fixed 4.15.0-1045.50
	18.10 cosmic	Ignored end of life, was pending
	18.04 LTS bionic	Fixed 4.15.0-1045.50
	16.04 LTS xenial	Ignored end of standard support, was needed
	14.04 LTS trusty	Not in release
linux-oem-6.11	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-oem-6.8	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-oracle	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Not affected
	19.04 disco	Fixed 4.15.0-1017.19
	18.10 cosmic	Ignored end of life, was pending
	18.04 LTS bionic	Fixed 4.15.0-1017.19
	16.04 LTS xenial	Fixed 4.15.0-1017.19~16.04.2
	14.04 LTS trusty	Not in release
linux-oracle-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-oracle-5.4	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-oracle-6.8	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-raspi	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-raspi-5.4	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-raspi-realtime	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-raspi2	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Ignored replaced by linux-raspi
	19.10 eoan	Not affected
	19.04 disco	Fixed 5.0.0-1012.12
	18.10 cosmic	Fixed 4.18.0-1018.21
	18.04 LTS bionic	Fixed 4.15.0-1040.43
	16.04 LTS xenial	Fixed 4.4.0-1114.123
	14.04 LTS trusty	Not in release
linux-realtime	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-riscv	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Ignored end of kernel support
	20.04 LTS focal	Ignored superseded by linux-riscv-5.8
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-riscv-5.15	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-riscv-6.8	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-snapdragon	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not affected
	19.04 disco	Fixed 5.0.0-1016.17
	18.10 cosmic	Not in release
	18.04 LTS bionic	Fixed 4.15.0-1057.62
	16.04 LTS xenial	Fixed 4.4.0-1118.124
	14.04 LTS trusty	Not in release
linux-xilinx-zynqmp	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release

Notes

tyhicks

This issue is primarily due to the TCP spec not defining a minimum value for the Minimum Segment Size (MSS). The Linux kernel cannot safely put a restriction on the MSS because it may break valid TCP connections. This issue will be addressed by allowing a system administrator to raise the smallest acceptable MSS value but there will be no default mitigation by default.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
linux	Introduced by 1da177e, fixed by 5f3e2bf Introduced by 1da177e, fixed by 967c05a

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVE-2019-11479

Cvss 3 Severity Score