CVE-2026-31717

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate owner of durable handle on reconnect Currently, ksmbd does not verify if the user attempting to reconnect to a durable handle is the same user who originally opened the file. This allows any authenticated user to hijack an orphaned durable handle by predicting or brute-forcing the persistent ID. According to MS-SMB2, the server MUST verify that the SecurityContext of the reconnect request matches the SecurityContext associated with the existing open. Add a durable_owner structure to ksmbd_file to store the original opener's UID, GID, and account name. and catpure the owner information when a file handle becomes orphaned. and implementing ksmbd_vfs_compare_durable_owner() to validate the identity of the requester during SMB2_CREATE (DHnC).

Predictions

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

References

• https://git.kernel.org/stable/c/00ce8d6789dae72d042a4522264964c72891ca37
• https://git.kernel.org/stable/c/49110a8ce654bbe56bef7c5e44cce31f4b102b8a
• https://git.kernel.org/stable/c/c908c853f304a4969b5aa10eba0b50350cc65b80
• https://www.suse.com/security/cve/CVE-2026-31717.html
• https://security-tracker.debian.org/tracker/CVE-2026-31717