Out-of-bounds read in Valkey - CVE-2026-21863

Vulnerability identifier: #VU128025

CSH Severity: Medium

CVSS v4: 7.1 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-21863

CWE-ID: CWE-125

Exploitation vector: Adjecent network

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to out-of-bounds read in the clusterbus packet processing code when processing a malformed clusterbus ping extension packet. A remote attacker can send a specially crafted clusterbus packet to cause a denial of service.

Exploitation requires access to the Valkey clusterbus port.

Valkey
Debian Linux
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Real Time 15
Fedora
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Server Applications Module
openSUSE Leap
Ubuntu
redis (Debian package)
valkey (Ubuntu package)
valkey
valkey (Red Hat package)
valkey-devel
valkey-compat-redis
valkey-debuginfo
valkey-debugsource
valkey (Debian package)

Install security update from vendor's website.

Valkey - addressed in versions 7.2.12, 8.0.7, 8.1.6, 9.0.3
redis (Debian package) - addressed in versions 5:7.0.15-1~deb12u7, 8.0.2-3+deb13u2
valkey (Ubuntu package) - addressed in versions 7.2.12+dfsg1-0ubuntu0.1, 8.1.6+dfsg1-0ubuntu0.1
valkey - addressed in versions 8.0.7-1.el8, 8.0.7-1.fc42, 8.1.6-1.fc43, 9.0.3-1.fc44
valkey (Red Hat package) - addressed in versions 8.0.7-1.el9_7, 8.0.7-1.el10_0, 8.0.7-1.el10_1
valkey-devel - addressed in versions 8.0.7-150600.13.20.1, 8.0.7-150700.3.14.1
valkey-compat-redis - addressed in versions 8.0.7-150600.13.20.1, 8.0.7-150700.3.14.1
valkey-debuginfo - addressed in versions 8.0.7-150600.13.20.1, 8.0.7-150700.3.14.1
valkey - addressed in versions 8.0.7-150600.13.20.1, 8.0.7-150700.3.14.1
valkey-debugsource - addressed in versions 8.0.7-150600.13.20.1, 8.0.7-150700.3.14.1
valkey (Debian package) - update to 8.1.1+dfsg1-3+deb13u2

• https://github.com/valkey-io/valkey/security/advisories/GHSA-c677-q3wr-gggq

• Multiple vulnerabilities in Valkey
• Debian update for valkey
• Fedora 43 update for valkey
• Fedora 44 update for valkey
• Fedora 42 update for valkey
• Fedora EPEL 8 update for valkey
• Red Hat Enterprise Linux 10 update for valkey
• Red Hat Enterprise Linux 9 update for valkey
• Red Hat Enterprise Linux 10 update for valkey
• SUSE update for valkey
• SUSE update for valkey
• Ubuntu update for valkey
• Debian update for redis