# CVE-2026-64390: linux: In the Linux kernel, the following vulnerability has been resolved:  ksmbd: track the connection owning a byte-range...

CVE-2026-64390 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-64390, released August 1, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-64390
- Priority: High
- CVSS: 8.8 (high)
- EPSS: 0.0047
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 25, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  ksmbd: track the connection owning a byte-range lock  SMB2_LOCK adds each granted byte-range lock to both the file lock list and the lock list of the connection which handled the request.  The final close and durable handle paths, however, remove the connection list entry while holding fp->conn->llist_lock.  With SMB3 multichannel, the connection handling the LOCK request can be different from the connection which opened the file.  The entry can therefore be removed under a different spinlock from the one protecting the list it belongs to.  A concurrent traversal can then access freed struct ksmbd_lock and struct file_lock objects.  Record the connection owning each lock's clist entry and hold a reference to it while the entry is linked.  Use that connection and its llist_lock for unlock, rollback, close, and durable preserve.  Durable reconnect assigns the new connection as the owner when publishing the locks again.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.180-1 | [DEBIAN-CVE-2026-64390](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64390.md) | Aug 1, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.100-1 | [DEBIAN-CVE-2026-64390](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64390.md) | Aug 1, 2026 |
| Linux | linux Debian 14 | 7.1.4-1 | [DEBIAN-CVE-2026-64390](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64390.md) | Aug 1, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.100-1~deb12u1 | [DEBIAN-CVE-2026-64390](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64390.md) | Aug 1, 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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