CVE-2026-74637: perf/core: Fix group leader use-after-free after sibling detach

mediumCVSS 4.1CVE-2026-74637

CSIRTS triage

vendor: Linux product: Linux kernel Memory corruption

What: A use-after-free vulnerability in perf event group leader handling occurs when sibling events are detached.
Who is affected: Systems running vulnerable Linux kernel versions with perf events subsystem active.
Urgency: Medium priority; not currently exploited but use-after-free enables privilege escalation and system compromise.
Action: Apply kernel patch fixing perf group leader reference counting in kernel/events/core.c or update to patched kernel version.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 4.1
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74637

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-746370.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-74637	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for perf/core

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-74637: In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix group leade…nvd · 2026-08-22
highCVE-2026-64556: perf/core: Detach event groups during remove_on_execmsrc · 2026-08-06
mediumCVE-2025-37878: perf/core: Fix WARN_ON(!ctx) in __free_event() for partial initmsrc · 2026-08-06
highCVE-2026-64556: In the Linux kernel, the following vulnerability has been resolved: perf/core: Detach event gr…nvd · 2026-07-29