Bug 2493755 (CVE-2026-53309)

Summary: CVE-2026-53309 kernel: ocfs2/dlm: fix off-by-one in dlm_match_regions() region comparison
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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OS: Linux   
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A flaw was found in the Linux kernel's OCFS2 Distributed Lock Manager (DLM) component. An off-by-one error in the `dlm_match_regions()` function's region comparison loop causes it to read beyond the valid memory range of `qr_regions`. This out-of-bounds read could lead to system instability or crashes.
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Description OSIDB Bzimport 2026-06-26 21:05:22 UTC 
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.
Comment 1 Mauro Matteo Cascella 2026-06-29 08:34:14 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062620-CVE-2026-53309-794d@gregkh/T