CVE-2026-53043

What it is

In the Linux kernel, the following vulnerability has been resolved: ocfs2/dlm: validate qr_numregions in dlm_match_regions() Patch series "ocfs2/dlm: fix two bugs in dlm_match_regions()". In dlm_match_regions(), the qr_numregions field from a DLM_QUERY_REGION network message is used to drive loops over the qr_regions buffer without sufficient validation. This series fixes two issues: - Patch 1 adds a bounds check to reject messages where qr_numregions exceeds O2NM_MAX_REGIONS. The o2net layer only validates message byte length; it does not constrain field values, so a crafted message can set qr_numregions up to 255 and trigger out-of-bounds reads past the 1024-byte qr_regions buffer. - Patch 2 fixes an off-by-one in the local-vs-remote comparison loop, which uses '<=' instead of '<', reading one entry past the valid range even when qr_numregions is within bounds. This patch (of 2): The qr_numregions field from a DLM_QUERY_REGION network message is used directly as loop bounds in dlm_match_regions() without checking against O2NM_MAX_REGIONS. Since qr_regions is sized for at most O2NM_MAX_REGIONS (32) entries, a crafted message with qr_numregions > 32 causes out-of-bounds reads past the qr_regions buffer. Add a bounds check for qr_numregions before entering the loops.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure, service disruption.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-06-24 17:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-07-14 19:27 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.5% in the next 30 days (EPSS).
• Severity: 9.1 CRITICAL (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-06-24 17:17 UTC

Last modified

2026-07-14 19:27 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-787 · Out-of-bounds write

Record status

Analyzed

Affected

• Linux Kernel < 5.10.258
• Linux Kernel < 5.15.209
• Linux Kernel < 6.1.175
• Linux Kernel < 6.6.141
• Linux Kernel < 6.12.91
• Linux Kernel < 6.18.33
• Linux Kernel < 7.0.10

Attack profile CVSS 3.1 · 9.1

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-53043.md and follow it. Check whether this project is affected by CVE-2026-53043. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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