CVE-2026-74637

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-08-22. a secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

perf/core: Fix group leader use-after-free after sibling detach

perf_group_detach() handles leader and sibling detach differently. When the group leader is detached, all siblings are promoted to singleton events and their group_leader pointer is reset to themselves. When a sibling is detached, it is removed from the leader's sibling_list, but its group_leader pointer is left pointing at the old leader.

That is harmless when the sibling is being closed and freed immediately, as in the DETACH_DEAD path. It is not safe when the sibling is detached but kept alive, such as during CPU hotplug with DETACH_GROUP. In that case the sibling is removed from the context, while its file descriptor can still keep it alive.

A typical failing sequence is:

  • A group contains leader L and sibling S.
  • CPU hot-unplug detaches S with DETACH_GROUP, removing it from
L->sibling_list but leaving S->group_leader == L.
  • L is later closed and freed.
  • A PERF_IOC_FLAG_GROUP ioctl on S follows S->group_leader and
dereferences the freed leader.

This was reproduced by running the perf event fuzzer, CPU hotplug, and a stress workload concurrently:

Unable to handle kernel paging request at virtual address 006b6b6b6b6b6cdb CPU: 2 PID: 12489 Comm: perf_fuzzer 6.18.7 PREEMPT pc : perf_ioctl+0x34c/0xc68 x20: ffffff89a3fa2c70 x8 : 6b6b6b6b6b6b6b6b Code: 943c4a0e 340047a0 f9404a94 f9411e88 (f940b908) Call trace: perf_ioctl+0x34c/0xc68 (P) __arm64_sys_ioctl+0xa0/0xf4 invoke_syscall+0x58/0xe4 el0_svc_common+0xa8/0xdc do_el0_svc+0x1c/0x28 el0_svc+0x40/0xc0 el0t_64_sync_handler+0x68/0xdc el0t_64_sync+0x1c4/0x1c8

The fault happened in perf_ioctl(), where perf_event_for_each() follows the stale group_leader pointer and perf_event_for_each_child() then dereferences the freed leader's context.

Fix the use-after-free by promoting the detached sibling to a singleton. Also fix __event_disable() cgroup accounting and event state change.

CVSS v3
7.8
EG Score
7.8(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

August 22, 2026

Last Modified

August 27, 2026

Advisory Details (4)

Auto-updated Aug 25, 2026
No patch confirmed yet.
generic

perf/core: Fix group leader use-after-free after sibling detach - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/42c5ca1f0a288a52878bd72a5595b08261057438
generic

perf/core: Fix group leader use-after-free after sibling detach - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1e7abfeb23c12bf46f6457e4a3e1a1a300d50619
generic

perf/core: Fix group leader use-after-free after sibling detach - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a979a642402d0b1f856c7a729b4cb2d92de4cf2f
generic

perf/core: Fix group leader use-after-free after sibling detach - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b42948f9e0d1ea4dbd5742ce1dfc7688de5d4a35

Vendor Advisories for CVE-2026-74637(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 31× in last 7d / 34× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 18:13 UTCGHSA enrichment
  3. 2026-08-29 05:21 UTCEG score recompute
  4. 2026-08-29 05:21 UTCGHSA enrichment
  5. 2026-08-28 21:42 UTCEPSS rescore
  6. 2026-08-28 16:29 UTCGHSA enrichment
  7. 2026-08-28 02:24 UTCEG score recompute
  8. 2026-08-28 02:24 UTCGHSA enrichment
  9. 2026-08-27 14:25 UTCEPSS rescore
  10. 2026-08-27 13:34 UTCEG score recompute
  11. 2026-08-27 13:34 UTCGHSA enrichment
  12. 2026-08-27 13:00 UTCEG score recompute
  13. 2026-08-27 13:00 UTCGHSA enrichment
  14. 2026-08-27 09:51 UTCGHSA enrichment
  15. 2026-08-26 20:59 UTCEG score recompute
  16. 2026-08-26 20:59 UTCGHSA enrichment
  17. 2026-08-26 14:47 UTCEPSS rescore
  18. 2026-08-26 08:09 UTCGHSA enrichment
  19. 2026-08-25 19:19 UTCEG score recompute
  20. 2026-08-25 19:19 UTCGHSA enrichment
  21. 2026-08-25 13:49 UTCEPSS rescore
  22. 2026-08-25 06:29 UTCEG score recompute
  23. 2026-08-25 06:29 UTCGHSA enrichment
  24. 2026-08-25 05:56 UTCEG score recompute▲ 7.80
  25. 2026-08-25 05:56 UTCGHSA enrichment
Show 9 more
  1. 2026-08-25 05:55 UTCMITRE cvelistV5CVSS v3 → 7.8 · severity → HIGH
  2. 2026-08-24 14:18 UTCEPSS rescore
  3. 2026-08-23 13:19 UTCGHSA enrichment
  4. 2026-08-23 13:19 UTCNVD update
  5. 2026-08-23 13:06 UTCGHSA enrichment
  6. 2026-08-23 13:05 UTCMITRE cvelistV5
  7. 2026-08-22 16:24 UTCNVD update
  8. 2026-08-22 15:41 UTCEG score recompute
  9. 2026-08-22 15:35 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-74637?
CVE-2026-74637 is a high vulnerability published on August 22, 2026. In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix group leader use-after-free after sibling detach perfgroupdetach() handles leader and sibling detach differently. When the group leader is detached, all siblings are promoted to singleton events and their…
When was CVE-2026-74637 disclosed?
CVE-2026-74637 was first published in the National Vulnerability Database on August 22, 2026, with the most recent update on August 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74637 actively exploited?
CVE-2026-74637 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.5% of all scored CVEs.
What is the CVSS score of CVE-2026-74637?
CVE-2026-74637 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-74637?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-74637, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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