CVE-2026-43499

High

In the Linux kernel, the following vulnerability has been resolved: rtmutex: Use waiter::task instead of current in remove_waiter() remove_waiter() is used by the slowlock paths, but it is also used for proxy-lock rollback in rt_mutex_start_proxy_lock() when invoked from futex_requeue(). In the latter case waiter::task is not current, but remove_waiter() operates on current for the dequeue operation. That results in several problems: 1) the rbtree dequeue happens without waiter::task::pi_lock being held 2) the waiter task's pi_blocked_on state is not cleared, which leaves a dangling pointer primed for UAF around. 3) rt_mutex_adjust_prio_chain() operates on the wrong top priority waiter task Use waiter::task instead of current in all related operations in remove_waiter() to cure those problems. [ tglx: Fixup rt_mutex_adjust_prio_chain(), add a comment and amend the changelog ]

Package Linux Kernel
Published 2026-05-21
Last modified 2026-07-24
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

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

Weakness type

CWE-416

CVE-2026-43499 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 2.6.39 and later are affected. Fixed in 5.10.261, 5.15.212, 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1 and their respective stable series.

Affected from
≥ 2.6.39
Fixed in
✓ 5.10.261 5.10.x ✓ 5.15.212 5.15.x ✓ 6.1.175 6.1.x ✓ 6.6.140 6.6.x ✓ 6.12.86 6.12.x ✓ 6.18.27 6.18.x ✓ 7.0.4 7.0.x ✓ 7.1

References

9 total
Showing 5 of 9 references View all on NVD

Frequently asked questions

  • What is CVE-2026-43499?

    CVE-2026-43499 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 2.6.39 onward and has been patched in 5.10.261, 5.15.212, 6.1.175 and others. CVE-2026-43499 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-43499?

    CVE-2026-43499 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-43499?

    Yes. CVE-2026-43499 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.175 and others. If you are running Linux kernel 2.6.39 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-43499 actively exploited?

    No. CVE-2026-43499 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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