CVE-2026-43376

critical

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().

References

https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde

https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a

https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294

https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e

https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c

Details

Source: Mitre, NVD

Published: 2026-05-08

Updated: 2026-05-12

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.8

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

Severity: Critical

EPSS

EPSS: 0.00018