CVE-2026-63802: blk-cgroup: fix UAF in __blkcg_rstat_flush()

highCVSS 7.8CVE-2026-63802

CSIRTS triage

vendor: Linux product: blk-cgroupOther

What: There is a use-after-free vulnerability in __blkcg_rstat_flush().
Who is affected: Deployments of blk-cgroup are affected.
Urgency: Remediation is critical as use-after-free vulnerabilities can be exploited.
Action: Patch to the latest version to resolve the vulnerability.

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: high — CVSS 7.8
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63802

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-2026-638020.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-63802	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 blk-cgroup

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-2026-63802: In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix UAF in __b…nvd · 2026-07-19
mediumCVE-2026-53126: blk-cgroup: fix disk reference leak in blkcg_maybe_throttle_current()msrc · 2026-06-09