Kernel compromise via stale perf group leader
Published Aug 22, 2026 · Updated Aug 25, 2026
Use-after-free in Linux perf/core allows local users to gain kernel privileges or crash the system through perf event group ioctls. perf_group_detach removes a live sibling from sibling_list during DETACH_GROUP but leaves group_leader pointing to the freed leader, which perf_ioctl later dereferences. Basic unprivileged local access suffices through self-monitoring perf events under the default perf_event_paranoid setting; no network path or action by another user is required.
Summary
What happened
Use-after-free in Linux perf/core allows local users to gain kernel privileges or crash the system through perf event group ioctls. perf_group_detach removes a live sibling from sibling_list during DETACH_GROUP but leaves group_leader pointing to the freed leader, which perf_ioctl later dereferences. Basic unprivileged local access suffices through self-monitoring perf events under the default perf_event_paranoid setting; no network path or action by another user is required.
The record
- CVE
- CVE-2026-74637
- Published
- Aug 22, 2026
- Updated
- Aug 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-825, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 22, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.6.34.14 <2.6.35
- Affected versionversion=2.6.35
- Affected versionversion=8a49542c0554af7d0073aac0ee73ee65b807ef34 <1e7abfeb23c12bf46f6457e4a3e1a1a300d50619
- Affected versionversion=8a49542c0554af7d0073aac0ee73ee65b807ef34 <42c5ca1f0a288a52878bd72a5595b08261057438
- Affected versionversion=8a49542c0554af7d0073aac0ee73ee65b807ef34 <a979a642402d0b1f856c7a729b4cb2d92de4cf2f
- Affected versionversion=8a49542c0554af7d0073aac0ee73ee65b807ef34 <b42948f9e0d1ea4dbd5742ce1dfc7688de5d4a35
- Affected versionversion=e732ebc42aea321ee84514330eb3a675307fcc83
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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