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CVE intelligence

CVE-2026-53309

Vulnerability intelligence

Published Jun 26, 2026Sources checked Oct 27, 2026
9.8CRITICALCVSS out of 10
What this means

Review the available evidence

CVE-2026-53309 and is rated Critical severity with a CVSS score of 9.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Ubuntu Security Notices guidance

Vendor revision: Oct 9, 2026

This update corrects flaws in the following subsystems: - Hardware crypto device drivers; - NVIDIA Tegra memory controller driver; - Network drivers; - USB core drivers; - GFS2 file system; - OCFS2 file system; - SMB network file system; - SoundWire (SDCA) ASoC drivers; - B.A.T.M.A.N.

Ubuntu Security Notices guidance

Vendor revision: Sep 30, 2026

This update corrects flaws in the following subsystems: - Network file system (NFS) server daemon; - OCFS2 file system; - IPv6 networking; - Netfilter; - SCTP protocol; (CVE-2025-38724, CVE-2026-53043, CVE-2026-53131, CVE-2026-53221, CVE-2026-53224, CVE-2026-53225, CVE-2026-53246, CVE-2026-53309)

Ubuntu Security Notices guidance

Vendor revision: Sep 18, 2026

This update corrects flaws in the following subsystems: - NVIDIA Tegra memory controller driver; - File systems infrastructure; - Network file system (NFS) server daemon; - OCFS2 file system; - B.A.T.M.A.N.

CISA KEVNot listedBased on the latest collected catalog
EPSS0.4%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview

What is CVE-2026-53309?

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.

Source: NVD