What is CVE-2026-53309?

CVE-2026-53309 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 2.6.37 onward and patched in 5.10.258, 5.15.209, 6.1.175 and others. CVE-2026-53309 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-53309?

CVE-2026-53309 has a CVSS score of 9.8 out of 10, rated Critical severity. 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-2026-53309?

Yes, CVE-2026-53309 has been patched. Fixed versions include 5.10.258, 5.15.209, 6.1.175 and others. If you are running Linux kernel 2.6.37 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-53309 actively exploited?

CVE-2026-53309 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-53309

Critical

In the Linux kernel, the following vulnerability has been resolved: ocfs2/dlm: fix off-by-one in dlm_match_regions() region comparison The local-vs-remote region comparison loop uses '<=' instead of '<', causing it to read one entry past the valid range of qr_regions. The other loops in the same function correctly use '<'. Fix the loop condition to use '<' for consistency and correctness.

Package Linux Kernel

Published 2026-06-26

Last modified 2026-07-06

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-193

CVE-2026-53309 is classified as CWE-193

See CWE-193 on MITRE CWE for full details on this weakness type.

Affected versions

Linux kernel versions 2.6.37 and later are affected. Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, 7.0.10, 7.1 and their respective stable series.

Affected from

≥ 2.6.37

Fixed in

✓ 5.10.258 5.10.x ✓ 5.15.209 5.15.x ✓ 6.1.175 6.1.x ✓ 6.6.141 6.6.x ✓ 6.12.91 6.12.x ✓ 6.18.33 6.18.x ✓ 7.0.10 7.0.x ✓ 7.1

References

8 total

Kernel Git
https://git.kernel.org/stable/c/01b61e8dda9b0fdb0d4cda43de25f4e390554d7b

Patch
Kernel Git
https://git.kernel.org/stable/c/1fb7f356547d9688822315cd2b205ff0bd5429b4

Patch
Kernel Git
https://git.kernel.org/stable/c/2a0673836f019e7c032acbf48d022d5ccf02a845

Patch
Kernel Git
https://git.kernel.org/stable/c/426cd8eedac89b86148d4478990eeef16e8a2520

Patch
Kernel Git
https://git.kernel.org/stable/c/760ab35040aca8399021fdb9ff1db1089feb7194

Patch

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2026-53309

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-06-26

Modified 2026-07-06

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-53309?

CVE-2026-53309 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 2.6.37 onward and has been patched in 5.10.258, 5.15.209, 6.1.175 and others. CVE-2026-53309 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-53309?

CVE-2026-53309 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-2026-53309?

Yes. CVE-2026-53309 has been patched. Fixed versions include 5.10.258, 5.15.209, 6.1.175 and others. If you are running Linux kernel 2.6.37 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-53309 actively exploited?

No. CVE-2026-53309 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.