High severity · published May 1, 2026
CVE-2026-31717
ksmbd: validate owner of durable handle on reconnect
8.8
CVSS
0.4%
EPSS
No
On KEV
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).
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
6.6.32 before 6.7; 6.9 before 6.18.25; 6.19 before 7.0.2; 7.1 · source: NVD
LI
Linux · Linux
8df4bcdb0a4232192b2445256c39b787d58ef14d before 712cdf917e77a6444ce3836874829d770db20ee6; c8efcc786146a951091588e5fa7e3c754850cb3c before c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d; c8efcc786146a951091588e5fa7e3c754850cb3c before 00ce8d6789dae72d042a4522264964c72891ca37; c8efcc786146a951091588e5fa7e3c754850cb3c before c908c853f304a4969b5aa10eba0b50350cc65b80; c8efcc786146a951091588e5fa7e3c754850cb3c before 49110a8ce654bbe56bef7c5e44cce31f4b102b8a; 6.6.32 before 6.6.142; +1 more · source: vendor