CVE-2026-21863

Server crash via unchecked clusterbus ping extension

Published Feb 23, 2026 · Updated Feb 23, 2026

Out-of-bounds read in Valkey before 7.2.12, 8.0.7, or 8.1.6, and 9.0.0 through 9.0.2 allows remote attackers to crash it via clusterbus. The clusterbus packet parser reads a ping extension without first verifying that the extension lies inside the received packet buffer. Reachability requires access to the clusterbus port, and a malformed packet can terminate the Valkey process without disclosing or modifying data.

CVSS severity6.5
Medium
EPSS probability0.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds read in Valkey before 7.2.12, 8.0.7, or 8.1.6, and 9.0.0 through 9.0.2 allows remote attackers to crash it via clusterbus. The clusterbus packet parser reads a ping extension without first verifying that the extension lies inside the received packet buffer. Reachability requires access to the clusterbus port, and a malformed packet can terminate the Valkey process without disclosing or modifying data.

The record

CVE
CVE-2026-21863
Published
Feb 23, 2026
Updated
Feb 23, 2026
Vendor
Valkey
Product
Valkey
Classifications
CWE-125, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 7.2.12
  2. Affected versionversion=>= 8.0.0, < 8.0.7
  3. Affected versionversion=>= 8.1.0, < 8.1.6
  4. Affected versionversion=>= 9.0.0, < 9.0.2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Valkey · Valkeyversion=< 7.2.12; version=>= 8.0.0, < 8.0.7; version=>= 8.1.0, < 8.1.6; version=>= 9.0.0, < 9.0.2

Published CVSS scores

7.5redhat-SADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.5GitHub, Inc.CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo