CVE-2026-64370: posix-cpu-timers: Fix pid refcount leak in do_cpu_nanosleep() error path

mediumCVSS 5.5CVE-2026-64370

CSIRTS triage

vendor: Linux product: posix-cpu-timersOther

What: There is a pid refcount leak vulnerability in the do_cpu_nanosleep() error path.
Who is affected: Deployments of the posix-cpu-timers are affected.
Urgency: Remediation is necessary to prevent potential exploitation, although exploitation status is currently unknown.
Action: Update to the latest version of the posix-cpu-timers.

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 5.5
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64370

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-2026-643700.18% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 7% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-64370	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

unknownCVE-2026-64370: In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: Fix pid …nvd

Recent advisories for posix-cpu-timers

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-2026-64560: posix-cpu-timers: Prevent UAF caused by non-leader exec() racemsrc · 2026-08-06
highCVE-2026-64560: In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: Prevent …nvd · 2026-07-29
unknownCVE-2026-64370: In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: Fix pid …nvd · 2026-07-25