CVE-2020-14386

Published: 4 September 2020

A flaw was found in the Linux kernel before 5.9-rc4. Memory corruption can be exploited to gain root privileges from unprivileged processes. The highest threat from this vulnerability is to data confidentiality and integrity.

From the Ubuntu Security Team

Or Cohen discovered that the AF_PACKET implementation in the Linux kernel did not properly perform bounds checking in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Notes

requires CAP_NET_RAW

Added break as investigated by Solar Designer.

older backports without 8e8e2951e309 will need second
lore.kernel.org variant

Mitigation

If unprivileged user namespaces are not needed, set the
kernel.unprivileged_userns_clone sysctl to 0; e.g.
  $ sudo sysctl kernel.unprivileged_userns_clone=0

Status

Severity score breakdown

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14386
• https://www.openwall.com/lists/oss-security/2020/09/03/3
• https://www.openwall.com/lists/oss-security/2020/09/04/2
• https://lore.kernel.org/netdev/20200904040528.3635711-1-edumazet@google.com/T/#u
• https://lore.kernel.org/netdev/20200904133052.20299-1-snu@amazon.com/
• https://ubuntu.com/security/notices/USN-4489-1
• NVD
• Launchpad
• Debian