# CVE-2026-31717: ksmbd: validate owner of durable handle on reconnect

CVE-2026-31717 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-31717, released May 15, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-31717
- Priority: High
- CVSS: 8.8 (Important)
- EPSS: 0.0044
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 1, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/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).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.94-1 | [DEBIAN-CVE-2026-31717](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31717.md) | May 15, 2026 |
| Linux | linux Debian 14 | 7.0.3-1 | [DEBIAN-CVE-2026-31717](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31717.md) | May 15, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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