# CVE-2026-52911: ksmbd: scope conn->binding slowpath to bound sessions only

CVE-2026-52911 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-52911, released June 24, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-52911
- Priority: High
- CVSS: 8.8 (Important)
- EPSS: 0.0066
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 21, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-52911

## Description

In the Linux kernel, the following vulnerability has been resolved:  ksmbd: scope conn->binding slowpath to bound sessions only  When the binding SESSION_SETUP sets conn->binding = true, the flag stays set after the call so that the global session lookup in ksmbd_session_lookup_all() can find the session, which was not added to conn->sessions. Because the flag is connection-wide, the global lookup path will also resolve any other session by id if asked.  Tighten the global lookup so that the returned session must have this connection registered in its channel xarray (sess->ksmbd_chann_list). The channel entry is installed by the existing binding_session path in ntlm_authenticate()/krb5_authenticate() when a SESSION_SETUP completes successfully, so this condition is a strict equivalent of "this connection has been accepted as a channel of this session". Connections that have not bound to a given session cannot reach it via the global table.  The existing conn->binding gate for entering the slowpath is preserved so that non-binding connections keep the fast-path-only behavior, and the session->state check is unchanged.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.176-1 | [DEBIAN-CVE-2026-52911](https://patchblox.com/security/data/fix/linux/debian-cve-2026-52911.md) | Jun 24, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.94-1 | [DEBIAN-CVE-2026-52911](https://patchblox.com/security/data/fix/linux/debian-cve-2026-52911.md) | Jun 24, 2026 |
| Linux | linux Debian 14 | 7.0.10-1 | [DEBIAN-CVE-2026-52911](https://patchblox.com/security/data/fix/linux/debian-cve-2026-52911.md) | Jun 24, 2026 |

---

Data as of 2026-11-09T13:31:49Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.