CVE-2026-43376

Critical

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().

Package Linux Kernel
Published 2026-05-08
Last modified 2026-05-15
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

9.8

out of 10
Critical
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness type

CWE-416

CVE-2026-43376 is a Use After Free vulnerability

What is Use After Free?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.6.88, 6.12.25, 6.14.4, 6.15 and later are affected. Fixed in 6.6.130, 6.12.78, 6.18.19, 6.19.9, 7.0 and their respective stable series.

Affected from
≥ 6.6.88 ≥ 6.12.25 ≥ 6.14.4 ≥ 6.15
Fixed in
✓ 6.6.130 6.6.x ✓ 6.12.78 6.12.x ✓ 6.18.19 6.18.x ✓ 6.19.9 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43376 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

5 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2026-43376?

    CVE-2026-43376 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 6.6.88 onward and has been patched in 6.6.130, 6.12.78, 6.18.19 and others. CVE-2026-43376 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-43376?

    CVE-2026-43376 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-43376?

    Yes — CVE-2026-43376 has been patched. Fixed versions include 6.6.130, 6.12.78, 6.18.19 and others. If you are running Linux kernel 6.6.88 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-43376 actively exploited?

    No — CVE-2026-43376 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Use After Free (CWE-416)?

    The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. View CWE-416 on MITRE CWE →

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