Use After Free in Linux

CVE-2026-43376

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().

Vulnerability class: Use-After-Free

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (49.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-43376: held from 0.004 to 0.007.

EPSS over last 30 days · oldest: 0.004 · newest: 0.007 · change: +0.002

Affected products

  • Linux — versions 296cb5457cc6f4a754c4ae29855f8a253d52bcc6, d73686367ad68534257cd88a36ca3c52cb8b81d8, 6.6.88
  • Linux Kernel — versions 6.15, 7.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-43376?
CVE-2026-43376 is a critical-severity vulnerability in Linux, classified under Use After Free. CVSS score: 9.8/10. Published 2026-05-08.
How severe is CVE-2026-43376?
Critical severity. CVSS v3 base score is 9.8 out of 10.