Service interruption via unpinned DLM context release
Published Aug 15, 2026 · Updated Aug 15, 2026
Use-after-free in the Linux kernel OCFS2 DLM allows local users to interrupt service by racing locking_state debugfs open with teardown. debug_lockres_open() ignores a failed dlm_grab(), stores an unpinned dlm_ctxt pointer, and debug_lockres_release() later passes it to dlm_put() after teardown frees it. Exploitation requires permission to access the root-only debugfs tree by default, an OCFS2 domain, and concurrency with the last domain unregister; the demonstrated result is a kernel memory-safety fault with availability impact.
Summary
What happened
Use-after-free in the Linux kernel OCFS2 DLM allows local users to interrupt service by racing locking_state debugfs open with teardown. debug_lockres_open() ignores a failed dlm_grab(), stores an unpinned dlm_ctxt pointer, and debug_lockres_release() later passes it to dlm_put() after teardown frees it. Exploitation requires permission to access the root-only debugfs tree by default, an OCFS2 domain, and concurrency with the last domain unregister; the demonstrated result is a kernel memory-safety fault with availability impact.
The record
- CVE
- CVE-2026-74348
- Published
- Aug 15, 2026
- Updated
- Aug 15, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 15, 2026CVE publishedPublication date reported by the CVE source.
- Aug 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=2.6.26
- Affected versionversion=4e3d24ed1a1285fe3289653aacc965642706bacb <03ad858ce8064861ea580021976dc19b7aabb549
- Affected versionversion=4e3d24ed1a1285fe3289653aacc965642706bacb <5bee5d5f67aedd26d2b72e00e49dd93331fbcc30
- Affected versionversion=4e3d24ed1a1285fe3289653aacc965642706bacb <6cc93dea4078cbcddee63fa2234e382a76600464
- Affected versionversion=4e3d24ed1a1285fe3289653aacc965642706bacb <90a6512425414098a63fc97b77bed089c75d106b
- Affected versionversion=4e3d24ed1a1285fe3289653aacc965642706bacb <9c81c1a61a52b6ecf0d14f1dbd95f154a7a9e92a
- Affected versionversion=4e3d24ed1a1285fe3289653aacc965642706bacb <a087b2d3411e7f9df71ba3293596923ee2c70d65
- Affected versionversion=4e3d24ed1a1285fe3289653aacc965642706bacb <a09831214912a1f270663d935613910fafd8d883
- Affected versionversion=4e3d24ed1a1285fe3289653aacc965642706bacb <aa7883b6a3c76301a3299deb34de948e73bb6a08
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Technologies
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