CVE-2020-25212

A TOCTOU mismatch in the NFS client code in the Linux kernel before 5.8.3 could be used by local attackers to corrupt memory or possibly have unspecified other impact because a size check is in fs/nfs/nfs4proc.c instead of fs/nfs/nfs4xdr.c, aka CID-b4487b935452.

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. This can cause the product to perform invalid actions when the resource is in an unexpected state.

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://lists.opensuse.org/opensuse-security-announce/2020-10/msg00021.html
• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00035.html
• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00042.html
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.8.3
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b4487b93545214a9db8cbf32e86411677b0cca21
• https://lists.debian.org/debian-lts-announce/2020/09/msg00025.html
• https://lists.debian.org/debian-lts-announce/2020/10/msg00032.html
• https://lists.debian.org/debian-lts-announce/2020/10/msg00034.html
• https://twitter.com/grsecurity/status/1303370421958578179
• https://usn.ubuntu.com/4525-1/
• https://usn.ubuntu.com/4527-1/
• https://usn.ubuntu.com/4578-1/