CVE-2026-63639: Valkey: UAF in stream deserialization may lead to remote code execution

highCVSS 8.8CVE-2026-63639

CSIRTS triage

vendor: Valkey product: Valkey Unsafe deserialization Remote code execution

What: Valkey contains a use-after-free vulnerability in stream deserialization that allows remote code execution.
Who is affected: Valkey deployments accepting stream data from untrusted sources or via exposed network interfaces.
Urgency: Critical severity (CVSS 8.8) and not yet exploited; immediate patching is essential before potential weaponization.
Action: Apply the latest Valkey security patch addressing use-after-free in stream deserialization code.

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 8.8
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63639

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-2026-636390.89% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 57% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-63639	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

highCVE-2026-63639: Valkey is a distributed key-value database. Prior to 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1, …nvd

Recent advisories for Valkey

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-2026-63639: Valkey is a distributed key-value database. Prior to 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1, …nvd · 2026-08-18
highCVE-2026-56684: Valkey is a distributed key-value database. Prior to 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1, …nvd · 2026-08-18
highCVE-2026-56684: Valkey: TLS pending-data processing use-after-free may allow remote code executionmsrc · 2026-08-11
highCVE-2026-27623: Valkey has Pre-Authentication DOS from malformed RESP requestmsrc · 2026-08-06