CVE-2026-31717
Received
Received - Intake
ksmbd Durable Handle Owner Validation Flaw
Publication date: 2026-05-01
Last updated on: 2026-06-01
Assigner: kernel.org
Description
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 Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | From 6.6.32 (inc) to 6.7 (exc) |
| linux | linux_kernel | 7.1 |
| linux | linux_kernel | From 6.19 (inc) to 7.0.2 (exc) |
| linux | linux_kernel | From 6.9 (inc) to 6.18.25 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
