Malformed Valkey Cluster bus message can lead to Remote DoS

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Summary

CVECVE-2026-21863
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-02-23 20:28:53 UTC
Updated2026-07-15 02:18:31 UTC
DescriptionValkey 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-125 | CWE-125 CWE-125: Out-of-bounds Read | CWE-125 Out-of-bounds Read

VersionSourceTypeScoreSeverityVector
3.1ADPCVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.10b0ca135-0b70-47e7-9f44-1890c2a1c46cSecondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Lfprojects Valkey All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Valkey-io Valkey affected < 7.2.12 Not specified
CNA Valkey-io Valkey affected >= 8.0.0, < 8.0.7 Not specified
CNA Valkey-io Valkey affected >= 8.1.0, < 8.1.6 Not specified
CNA Valkey-io Valkey affected >= 9.0.0, < 9.0.2 Not specified
ADP Red Hat Red Hat Enterprise Linux 10 unaffected 0:8.0.7-1.el10_1 * rpm Not specified
ADP Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support unaffected 0:8.0.7-1.el10_0 * rpm Not specified
ADP Red Hat Red Hat Enterprise Linux 9 unaffected 0:8.0.7-1.el9_7 * rpm Not specified
ADP Red Hat Red Hat Hardened Images unaffected 9.0.3-1.2.hum1 * rpm Not specified

References

ReferenceSourceLinkTags
github.com/valkey-io/valkey/security/advisories/GHSA-c677-q3wr-gggq [email protected] github.com Vendor Advisory
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-21863.json 0b0ca135-0b70-47e7-9f44-1890c2a1c46c security.access.redhat.com
access.redhat.com/errata/RHSA-2026:3443 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
bugzilla.redhat.com/show_bug.cgi 0b0ca135-0b70-47e7-9f44-1890c2a1c46c bugzilla.redhat.com
access.redhat.com/security/cve/CVE-2026-21863 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:3507 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:5445 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
access.redhat.com/errata/RHSA-2026:8753 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

SourceTimeEvent
ADP2026-02-23T21:03:12.281ZReported to Red Hat.
ADP2026-02-23T19:41:28.783ZMade public.

Solutions

ADP: RHSA-2026:5445: Red Hat Enterprise Linux AppStream EUS (v. 10.0)

ADP: RHSA-2026:3443: Red Hat Enterprise Linux AppStream (v. 10)

ADP: RHSA-2026:3507: Red Hat Enterprise Linux AppStream (v. 9)

ADP: RHSA-2026:8753: Red Hat Hardened Images

Workarounds

ADP: To mitigate this issue, restrict network access to the Valkey cluster bus port. Configure network access control lists (ACLs) or firewall rules to ensure that only trusted hosts can connect to the cluster bus port. This limits the attack surface by preventing unauthorized actors from sending malicious clusterbus packets.

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