Out-of-bounds Read in Lfprojects Valkey

CVE-2026-21863

Valkey is a distributed key-value database. Prior to versions 9.0.2, 8.1.6, 8.0.7, and 7.2.12, a malicious actor with access to the Valkey clusterbus port can send an invalid packet that may cause an out bound read, which might result in the system crashing. The Valkey clusterbus packet processing code does not validate that a clusterbus ping extension packet is located within buffer of the clusterbus packet before attempting to read it. Versions 9.0.2, 8.1.6, 8.0.7, and 7.2.12 fix the issue. As an additional mitigation, don't expose the cluster bus connection directly to end users, and protect the connection with its own network ACLs.

Vulnerability class: Buffer Overflow

EPSS: 0.008 (52.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-21863?
CVE-2026-21863 is a high-severity vulnerability in Lfprojects Valkey, classified under Out-of-bounds Read. CVSS score: 7.5/10. Published 2026-02-23.
How severe is CVE-2026-21863?
High severity. CVSS v3 base score is 7.5 out of 10.