# CVE-2026-43376: linux: In the Linux kernel, the following vulnerability has been resolved:  ksmbd: fix use-after-free by using call_rcu() fo...

CVE-2026-43376 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-43376, released May 15, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-43376
- Priority: Urgent
- CVSS: 9.8 (critical)
- EPSS: 0.0044
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 8, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  ksmbd: fix use-after-free by using call_rcu() for oplock_info  ksmbd currently frees oplock_info immediately using kfree(), even though it is accessed under RCU read-side critical sections in places like opinfo_get() and proc_show_files().  Since there is no RCU grace period delay between nullifying the pointer and freeing the memory, a reader can still access oplock_info structure after it has been freed. This can leads to a use-after-free especially in opinfo_get() where atomic_inc_not_zero() is called on already freed memory.  Fix this by switching to deferred freeing using call_rcu().

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.85-1 | [DEBIAN-CVE-2026-43376](https://patchblox.com/security/data/fix/linux/debian-cve-2026-43376.md) | May 15, 2026 |
| Linux | linux Debian 14 | 6.19.10-1 | [DEBIAN-CVE-2026-43376](https://patchblox.com/security/data/fix/linux/debian-cve-2026-43376.md) | May 15, 2026 |

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Data as of 2026-11-08T00:53:09Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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