Use After Free in Valkey-Io Valkey

CVE-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, Valkey's RESTORE command accepts a malformed RDB stream payload that assigns one Pending Entry List NACK to multiple consumers during stream consumer-group deserialization, causing a use-after-free when one consumer is deleted while another still references the shared NACK and potentially allowing remote code execution. This issue is fixed in versions 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1.

Vulnerability class: Use-After-Free

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.012 (66.2th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 66.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-63639: held from 0.009 to 0.012.

EPSS over last 30 days · oldest: 0.009 · newest: 0.012 · change: +0.003

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-63639?
CVE-2026-63639 is a high-severity vulnerability in Valkey-Io Valkey, classified under Use After Free. CVSS score: 8.8/10. Published 2026-08-18.
How severe is CVE-2026-63639?
High severity. CVSS v3 base score is 8.8 out of 10.