What is CVE-2026-53166?

CVE-2026-53166 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a NULL Pointer Dereference flaw (CWE-476), affecting Linux kernel versions from 6.1.175 onward and patched in 6.2, 6.7, 6.13 and others. CVE-2026-53166 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-53166?

CVE-2026-53166 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2026-53166?

Yes, CVE-2026-53166 has been patched. Fixed versions include 6.2, 6.7, 6.13 and others. If you are running Linux kernel 6.1.175 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-53166 actively exploited?

CVE-2026-53166 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is NULL Pointer Dereference (CWE-476)?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/476.html

CVE-2026-53166

Medium

In the Linux kernel, the following vulnerability has been resolved: futex/requeue: Prevent NULL pointer dereference in remove_waiter() on self-deadlock When FUTEX_CMP_REQUEUE_PI requeues a non-top waiter that already owns the target PI futex, task_blocks_on_rt_mutex() returns -EDEADLK before setting waiter->task. The subsequent remove_waiter() in rt_mutex_start_proxy_lock() dereferences the NULL waiter->task, causing a kernel crash. Add a self-deadlock check for non-top waiters before calling rt_mutex_start_proxy_lock(), analogous to the top-waiter check in futex_lock_pi_atomic().

Package Linux Kernel

Published 2026-06-25

Last modified 2026-07-07

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-476

CVE-2026-53166 is a NULL Pointer Dereference vulnerability

What is NULL Pointer Dereference?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4 and later are affected. Fixed in 6.2, 6.7, 6.13, 6.18.36, 7.0.13 and their respective stable series.

Affected from

≥ 6.1.175 ≥ 6.6.140 ≥ 6.12.86 ≥ 6.18.27 ≥ 7.0.4

Fixed in

✓ 6.2 6.2.x ✓ 6.7 6.7.x ✓ 6.13 6.13.x ✓ 6.18.36 6.18.x ✓ 7.0.13 7.0.x

References

3 total

Kernel Git
https://git.kernel.org/stable/c/16f8e17184b31382076f84751db5ac51fc02733e

Patch
Kernel Git
https://git.kernel.org/stable/c/1f2f3f3eacd6653ab215c5d2ea70811148d433fc

Patch
Kernel Git
https://git.kernel.org/stable/c/74e144274af39935b0f410c0ee4d2b91c3730414

Patch

Details

CVE ID CVE-2026-53166

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-06-25

Modified 2026-07-07

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-53166?

CVE-2026-53166 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a NULL Pointer Dereference flaw (CWE-476) . It affects Linux kernel versions from 6.1.175 onward and has been patched in 6.2, 6.7, 6.13 and others. CVE-2026-53166 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-53166?

CVE-2026-53166 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2026-53166?

Yes. CVE-2026-53166 has been patched. Fixed versions include 6.2, 6.7, 6.13 and others. If you are running Linux kernel 6.1.175 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-53166 actively exploited?

No. CVE-2026-53166 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.