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CVE-2020-12656

Published: 5 May 2020

** DISPUTED ** gss_mech_free in net/sunrpc/auth_gss/gss_mech_switch.c in the rpcsec_gss_krb5 implementation in the Linux kernel through 5.6.10 lacks certain domain_release calls, leading to a memory leak. Note: This was disputed with the assertion that the issue does not grant any access not already available. It is a problem that on unloading a specific kernel module some memory is leaked, but loading kernel modules is a privileged operation. A user could also write a kernel module to consume any amount of memory they like and load that replicating the effect of this bug.

From the Ubuntu Security Team

It was discovered that the Kerberos SUNRPC GSS implementation in the Linux kernel did not properly deallocate memory on module unload. A local privileged attacker could possibly use this to cause a denial of service (memory exhaustion).

Notes

AuthorNote
sbeattie
upstream generally treats module unload as an unsafe
operation, which may explain a lack of progress in addressing the
issue.

Priority

Negligible

Cvss 3 Severity Score

5.5

Score breakdown

Status

Package Release Status
linux-oem-5.6
Launchpad, Ubuntu, Debian
focal
Released (5.6.0-1031.32)
groovy Does not exist

bionic Does not exist

eoan Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-hwe
Launchpad, Ubuntu, Debian
focal Does not exist

groovy Does not exist

bionic
Released (5.3.0-64.58~18.04.1)
eoan Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial
Released (4.15.0-115.116~16.04.1)
linux
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-115.116)
eoan Ignored
(end of life)
focal
Released (5.4.0-45.49)
groovy Not vulnerable
(5.8.0-16.17)
trusty Ignored
(was needs-triage ESM criteria)
upstream
Released (5.8~rc1)
xenial
Released (4.4.0-186.216)
Patches:
Introduced by

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2

Fixed by d47a5dc2888fd1b94adf1553068b8dad76cec96c
Introduced by

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2

Fixed by 24c5efe41c29ee3e55bcf5a1c9f61ca8709622e8
linux-aws
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-1080.84)
eoan Ignored
(end of life)
focal
Released (5.4.0-1022.22)
groovy Not vulnerable
(5.8.0-1004.4)
trusty Ignored
(was needs-triage ESM criteria)
upstream
Released (5.8~rc1)
xenial
Released (4.4.0-1111.123)
linux-aws-5.0
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-aws-5.3
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was pending)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-aws-5.4
Launchpad, Ubuntu, Debian
bionic
Released (5.4.0-1022.22~18.04.1)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-aws-hwe
Launchpad, Ubuntu, Debian
bionic Does not exist

eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial
Released (4.15.0-1080.84~16.04.1)
linux-azure
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Ignored
(end of life)
focal
Released (5.4.0-1023.23)
groovy Not vulnerable
(5.8.0-1004.4)
trusty
Released (4.15.0-1093.103~14.04.1)
Available with Ubuntu Pro or Ubuntu Pro (Infra-only)
upstream
Released (5.8~rc1)
xenial
Released (4.15.0-1093.103~16.04.1)
linux-azure-4.15
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-1093.103)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-azure-5.3
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-azure-5.4
Launchpad, Ubuntu, Debian
bionic
Released (5.4.0-1023.23~18.04.1)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-azure-edge
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-gcp
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Ignored
(end of life)
focal
Released (5.4.0-1022.22)
groovy Not vulnerable
(5.8.0-1002.2)
trusty Does not exist

upstream
Released (5.8~rc1)
xenial
Released (4.15.0-1081.92~16.04.1)
linux-gcp-4.15
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-1081.92)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-gcp-5.3
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-gcp-5.4
Launchpad, Ubuntu, Debian
bionic
Released (5.4.0-1022.22~18.04.1)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-gcp-edge
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-gke-4.15
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-1067.70)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-gke-5.0
Launchpad, Ubuntu, Debian
bionic
Released (5.0.0-1045.46)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-gke-5.3
Launchpad, Ubuntu, Debian
bionic
Released (5.3.0-1032.34~18.04.1)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-gke-5.4
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(5.4.0-1025.25~18.04.1)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-gkeop-5.4
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(5.4.0-1001.1)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-hwe-5.4
Launchpad, Ubuntu, Debian
bionic
Released (5.4.0-45.49~18.04.2)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-hwe-5.8
Launchpad, Ubuntu, Debian
bionic Does not exist

focal Not vulnerable
(5.8.0-23.24~20.04.1)
groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-hwe-edge
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Ignored
(end of life, was needs-triage)
linux-kvm
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-1072.73)
eoan Ignored
(end of life)
focal
Released (5.4.0-1021.21)
groovy Not vulnerable
(5.8.0-1001.1)
trusty Does not exist

upstream
Released (5.8~rc1)
xenial
Released (4.4.0-1077.84)
linux-lts-trusty
Launchpad, Ubuntu, Debian
bionic Does not exist

eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-lts-xenial
Launchpad, Ubuntu, Debian
bionic Does not exist

eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Ignored
(was needs-triage ESM criteria)
upstream
Released (5.8~rc1)
xenial Does not exist

linux-oem
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-1094.104)
eoan Ignored
(end of life)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Ignored
(end of standard support, was needs-triage)
linux-oem-osp1
Launchpad, Ubuntu, Debian
bionic
Released (5.0.0-1065.70)
eoan Ignored
(end of life)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-oracle
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-1051.55)
eoan Ignored
(end of life)
focal
Released (5.4.0-1022.22)
groovy Not vulnerable
(5.8.0-1001.1)
trusty Does not exist

upstream
Released (5.8~rc1)
xenial
Released (4.15.0-1051.55~16.04.1)
linux-oracle-5.0
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-oracle-5.3
Launchpad, Ubuntu, Debian
bionic Ignored
(end of life, was needs-triage)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-oracle-5.4
Launchpad, Ubuntu, Debian
bionic
Released (5.4.0-1022.22~18.04.1)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-raspi
Launchpad, Ubuntu, Debian
bionic Does not exist

eoan Does not exist

focal
Released (5.4.0-1016.17)
groovy Not vulnerable
(5.4.0-1016.17)
trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-raspi-5.4
Launchpad, Ubuntu, Debian
bionic
Released (5.4.0-1016.17~18.04.1)
focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-raspi2
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-1068.72)
eoan Ignored
(end of life)
focal Ignored
(end of life, was needs-triage)
groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial
Released (4.4.0-1136.145)
linux-raspi2-5.3
Launchpad, Ubuntu, Debian
bionic
Released (5.3.0-1030.32~18.04.2)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-riscv
Launchpad, Ubuntu, Debian
bionic Does not exist

eoan Does not exist

focal
Released (5.4.0-31.35)
groovy Not vulnerable
(5.8.0-1.1)
trusty Does not exist

upstream
Released (5.8~rc1)
xenial Does not exist

linux-snapdragon
Launchpad, Ubuntu, Debian
bionic
Released (4.15.0-1084.92)
eoan Does not exist

focal Does not exist

groovy Does not exist

trusty Does not exist

upstream
Released (5.8~rc1)
xenial
Released (4.4.0-1140.148)

Severity score breakdown

Parameter Value
Base score 5.5
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H