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Fencer Vulns
high 7.5

CVE-2026-21863 json

Malformed Valkey Cluster bus message can lead to Remote DoS

published 2026-02-23 8 mo ago modified 2026-09-08 2 mo ago also BIT-valkey-2026-21863 , EUVD-2026-7513 , GHSA-c677-q3wr-gggq

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami valkey 7.2.12, 8.0.7, 8.1.6, 9.0.2
  • Red Hat Red Hat Enterprise Linux 10 0:8.0.7-1.el10_1
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:8.0.7-1.el10_0
  • Red Hat Red Hat Enterprise Linux 9 0:8.0.7-1.el9_7
  • Red Hat Red Hat Hardened Images 9.0.3-1.2.hum1
  • redis Debian 12 5:7.0.15-1~deb12u7
  • redis Debian 13 5:8.0.2-3+deb13u2
  • redis Debian 14 5:8.0.6-1
  • redict Debian 14 7.3.6+ds-2
  • valkey Debian 13 8.1.1+dfsg1-3+deb13u2
  • valkey Debian 14 8.1.4+dfsg1-2

debian advisories DEBIAN-CVE-2026-21863

  • valkey Ubuntu 24.04 LTS 7.2.12+dfsg1-0ubuntu0.1
  • valkey Ubuntu 25.10 8.1.6+dfsg1-0ubuntu0.1

ubuntu advisories UBUNTU-CVE-2026-21863

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • valkey hummingbird 1 9.0.3-1.2.hum1
  • valkey-rdma hummingbird 1 9.0.3-1.2.hum1
  • valkey-compat-redis hummingbird 1 9.0.3-1.2.hum1
  • valkey RHEL 9 8.0.7-1.el9_7
  • valkey RHEL 10.1 8.0.7-1.el10_1
  • valkey enterprise linux eus 10.0 8.0.7-1.el10_0

red hat advisories RHSA-2026:8753RHSA-2026:5445RHSA-2026:3507RHSA-2026:3443

  • valkey SLE Module for Server Applications 15 SP7 8.0.7-150700.3.14.1
  • valkey openSUSE Leap 15.6 8.0.7-150600.13.20.1

suse advisories SUSE-SU-2026:0848-1SUSE-SU-2026:0685-1

  • valkey openSUSE Tumbleweed 9.0.3-1.1

opensuse advisories openSUSE-SU-2026:10266-1

  • valkey AlmaLinux 9 8.0.7-1.el9_7
  • valkey AlmaLinux 10 8.0.7-1.el10_1

almalinux advisories ALSA-2026:3507ALSA-2026:3443

  • valkey Rocky Linux 9 8.0.7-1.el9_7
  • valkey Rocky Linux 10 8.0.7-1.el10_1

rocky linux advisories RLSA-2026:3507RLSA-2026:3443

  • valkey Alpine 3.21 7.2.12-r0
  • valkey Alpine 3.22 8.1.6-r0
  • valkey Alpine 3.24, Alpine 3.23 9.0.3-r0

alpine advisories ALPINE-CVE-2026-21863

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • valkey Azure Linux 3.0 8.0.7-1

azure linux advisories AZL-78320

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-21863 updated cvss 7.5

valkey: Valkey: Denial of Service via invalid clusterbus packet

  • Red Hat Enterprise Linux AppStream (v. 9) valkey 8.0.7-1.el9_7
    fixed: vendor fix RHSA-2026:3507
  • Red Hat Enterprise Linux AppStream (v. 10) valkey 8.0.7-1.el10_1
    fixed: vendor fix RHSA-2026:3443
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) valkey 8.0.7-1.el10_0
    fixed: vendor fix RHSA-2026:5445
  • Red Hat Hardened Images valkey 9.0.3-1.2.hum1, valkey-compat-redis 9.0.3-1.2.hum1
    fixed: vendor fix RHSA-2026:8753

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.85% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami valkey
<7.2.12
>=8.0.0, <8.0.7
>=8.1.0, <8.1.6
>=9.0.0, <9.0.2
7.2.12
8.0.7
8.1.6
9.0.2

Affected products

  • valkey-io valkey
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Hardened Images

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.