Missing Authorization in Linux kernel - CVE-2026-97564

Vulnerability details

The vulnerability allows a local user to cause a root usermodehelper to process unvetted authority-bearing fields.

The vulnerability exists due to missing authorization validation in cifs.idmap key description handling when invoking request_key(2) with a non-NULL callout. A local user can supply a cifs.idmap key description containing authority-bearing fields to cause a root usermodehelper to process unvetted authority-bearing fields.

Affected software

How to mitigate CVE-2026-97564

External References

• https://git.kernel.org/stable/c/1d3b24b16a0b013792e8f1e3ed060f0b46f537d1
• https://git.kernel.org/stable/c/96751028c0d4dec785709ea3eb0ab38a4f2ded96
• https://git.kernel.org/stable/c/d9d7eeb0cea5b55b82888f443622fd8d4ee064f3
• https://git.kernel.org/stable/c/e5964064e3fbe6325893408faff08ca33de0e2c3

Related Security Bulletins

• Missing Authorization in Linux kernel smb client