CVE-2022-1966

Published: 3 June 2022

** REJECT ** DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: CVE-2022-32250. Reason: This candidate is a duplicate of CVE-2022-32250. Notes: All CVE users should reference CVE-2022-32250 instead of this candidate. All references and descriptions in this candidate have been removed to prevent accidental usage.

From the Ubuntu Security Team

Aaron Adams discovered that the netfilter subsystem in the Linux kernel did not properly handle the removal of stateful expressions in some situations, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code.

Mitigation

If not needed, disable the ability for unprivileged users
to create namespaces:
  $ sudo sysctl -w kernel.unprivileged_userns_clone=0
  $ echo kernel.unprivileged_userns_clone=0 | \
      sudo tee /etc/sysctl.d/99-disable-unpriv-userns.conf

References

• https://www.openwall.com/lists/oss-security/2022/05/31/1
• https://git.kernel.org/linus/520778042ccca019f3ffa136dd0ca565c486cedd
• https://ubuntu.com/security/notices/USN-5465-1
• https://ubuntu.com/security/notices/USN-5466-1
• https://ubuntu.com/security/notices/USN-5467-1
• https://ubuntu.com/security/notices/USN-5468-1
• https://ubuntu.com/security/notices/USN-5469-1
• https://ubuntu.com/security/notices/USN-5470-1
• https://ubuntu.com/security/notices/USN-5471-1
• https://www.cve.org/CVERecord?id=CVE-2022-1966
• NVD
• Launchpad
• Debian