CVE-2026-43376

ksmbd: fix use-after-free by using call_rcu() for oplock_info

State
Published
Severity
9.8 Critical
Published
May 8, 2026
Updated
Aug 5, 2026
Reserved
May 1, 2026

Read the record on cve.org

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().

Scores

CVSSScoreVectorSource
3.19.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HLinux

Weaknesses

The record names no weakness.

Affected Products

ProductVersions
LinuxLinux
  • 296cb5457cc6f4a754c4ae29855f8a253d52bcc6 to before 302fef75512b2c8329a3f5efab1ae7ba2562387aAffected
  • d54ab1520d43e95f9b2e22d7a05fc9614192e5a5 to before 08aa9f3c8cf4d0bee44df540dfe34e8d64069f2cAffected
  • 18b4fac5ef17f77fed9417d22210ceafd6525fc7 to before 1d6abf145615dbfe267ce3b0a271f95e3780e18eAffected
  • 18b4fac5ef17f77fed9417d22210ceafd6525fc7 to before ce8507ee82c888126d8e7565e27c016308d24cdeAffected
  • 18b4fac5ef17f77fed9417d22210ceafd6525fc7 to before 1dfd062caa165ec9d7ee0823087930f3ab8a6294Affected
  • d73686367ad68534257cd88a36ca3c52cb8b81d8Affected
  • 6.6.88 to before 6.6.130Affected
  • 6.12.25 to before 6.12.78Affected
  • 6.14.4 to before 6.15Affected
LinuxLinux
  • 6.15Affected
  • before 6.15Not affected
  • 6.6.130 through 6.6.*Not affected
  • 6.12.78 through 6.12.*Not affected
  • 6.18.19 through 6.18.*Not affected
  • 6.19.9 through 6.19.*Not affected
  • 7.0 and laterNot affected

References

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