CVE-2026-31717

Summary

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).

Affected Software

VendorProductVersion RangeStatus
LinuxLinux8df4bcdb0a4232192b2445256c39b787d58ef14d < 712cdf917e77a6444ce3836874829d770db20ee6affected
LinuxLinuxc8efcc786146a951091588e5fa7e3c754850cb3c < c7f0f0d01c88bdcb8b1694d7d321670013f7ed7daffected
LinuxLinuxc8efcc786146a951091588e5fa7e3c754850cb3c < 00ce8d6789dae72d042a4522264964c72891ca37affected
LinuxLinuxc8efcc786146a951091588e5fa7e3c754850cb3c < c908c853f304a4969b5aa10eba0b50350cc65b80affected
LinuxLinuxc8efcc786146a951091588e5fa7e3c754850cb3c < 49110a8ce654bbe56bef7c5e44cce31f4b102b8aaffected
LinuxLinux6.6.32 < 6.6.142affected
LinuxLinux6.9affected
LinuxLinux0 < 6.9unaffected
LinuxLinux6.6.142 <= 6.6.*unaffected
LinuxLinux6.12.92 <= 6.12.*unaffected
LinuxLinux6.18.25 <= 6.18.*unaffected
LinuxLinux7.0.2 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References