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Vulnerability record · CVE-2026-43376 · published 8 May 2026

CVE-2026-43376: Linux kernel use after free vulnerability

Linux · Linux Kernel

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().

9.8 CVSS 3.1 Critical EPSS 0.65% · top 50.8% CWE-416 · Use after free
9.8CVSS 3.1 base score
0.65%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
5References
17 Jun 2026Last modified by NVD

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().

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c Patch
https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e Patch
https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294 Patch
https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a Patch
https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde Patch

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Source: NIST National Vulnerability Database (record CVE-2026-43376), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.