CVE-2026-31717: ksmbd: validate owner of durable handle on reconnect
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).
Metrics
- CVSS v3.1
- 8.8
- Severity
- HIGH
- Fixed in
- 0
- Affected Products
- 2
Fix available
- Linux / Linux< 00ce8d6789dae72d042a4522264964c72891ca37 (from c8efcc786146a951091588e5fa7e3c754850cb3c) · < c908c853f304a4969b5aa10eba0b50350cc65b80 (from c8efcc786146a951091588e5fa7e3c754850cb3c) · < 49110a8ce654bbe56bef7c5e44cce31f4b102b8a (from c8efcc786146a951091588e5fa7e3c754850cb3c) · 8df4bcdb0a4232192b2445256c39b787d58ef14d · < 6.7 (from 6.6.32)
- Linux / Linux6.9Fixed in 0, 6.18.25, 7.0.2, 7.1-rc1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H