CVE-2021-26910

Firejail before 0.9.64.4 allows attackers to bypass intended access restrictions because there is a TOCTOU race condition between a stat operation and an OverlayFS mount operation.

Weakness

The product checks the state of a resource before using that resource, but the resource’s state can change between the check and the use in a way that invalidates the results of the check.

Affected Software

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/27.html
• https://cwe.mitre.org/data/definitions/29.html

References

• http://www.openwall.com/lists/oss-security/2021/02/09/1
• https://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834b
• https://github.com/netblue30/firejail/releases/tag/0.9.64.4
• https://lists.debian.org/debian-lts-announce/2021/02/msg00015.html
• https://security.gentoo.org/glsa/202105-19
• https://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/
• https://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txt
• https://www.debian.org/security/2021/dsa-4849
• http://www.openwall.com/lists/oss-security/2021/02/09/1
• https://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834b
• https://github.com/netblue30/firejail/releases/tag/0.9.64.4
• https://lists.debian.org/debian-lts-announce/2021/02/msg00015.html
• https://security.gentoo.org/glsa/202105-19
• https://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/
• https://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txt
• https://www.debian.org/security/2021/dsa-4849