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Vulnerability · Published Feb 23, 2026 · Assigned by GitHub_M

CVE-2026-21863Malformed Valkey Cluster bus message can lead to Remote DoS

High 7.5

In plain English

A high-severity out-of-bounds read in valkey from valkey-io. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 58% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.8%top 41.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10valkey8.0.7-1.el10_1ALSA-2026:3443
AlmaLinux:9valkey8.0.7-1.el9_7ALSA-2026:3507
AlmaLinux:10valkey-devel8.0.7-1.el10_1ALSA-2026:3443
AlmaLinux:9valkey-devel8.0.7-1.el9_7ALSA-2026:3507
Alpine:v3.21valkey7.2.12-r0ALPINE-CVE-2026-21863
Alpine:v3.22valkey8.1.6-r0ALPINE-CVE-2026-21863
Alpine:v3.23valkey9.0.3-r0ALPINE-CVE-2026-21863
Alpine:v3.24valkey9.0.3-r0ALPINE-CVE-2026-21863
Debian:14redict7.3.6+ds-2DEBIAN-CVE-2026-21863
Debian:12redis5:7.0.15-1~deb12u7DEBIAN-CVE-2026-21863
Debian:13redis5:8.0.2-3+deb13u2DEBIAN-CVE-2026-21863
Debian:14redis5:8.0.6-1DEBIAN-CVE-2026-21863
Debian:13valkey8.1.1+dfsg1-3+deb13u2DEBIAN-CVE-2026-21863
Debian:14valkey8.1.4+dfsg1-2DEBIAN-CVE-2026-21863
Rocky Linux:10valkey0:8.0.7-1.el10_1RLSA-2026:3443
Rocky Linux:9valkey0:8.0.7-1.el9_7RLSA-2026:3507
Ubuntu:24.04:LTSvalkey7.2.12+dfsg1-0ubuntu0.1UBUNTU-CVE-2026-21863
Ubuntu:25.10valkey8.1.6+dfsg1-0ubuntu0.1UBUNTU-CVE-2026-21863

Affected products (as reported)

VendorProductVersions
valkey-io valkey < 7.2.12>= 8.0.0, < 8.0.7>= 8.1.0, < 8.1.6>= 9.0.0, < 9.0.2

Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References