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ValkeyApplication · Lfprojects

CVE-2026-21863

HIGH · 7.5 CVSS v3.1 Published 2026-02-23
Fix available
A fix is available. Upgrade to 7.2.12 / 8.0.7 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A missing bounds check in Valkey's clusterbus packet processing allows an attacker with access to the clusterbus port to send a malformed packet that triggers an out-of-bounds read. The code fails to validate that a clusterbus ping extension packet is within the buffer boundaries before attempting to read it, leading to potential denial of service via crash.

MitigationUpgrade Valkey to version 9.0.2, 8.1.6, 8.0.7, or 7.2.12 or later. Additionally, restrict network access to the clusterbus port using firewalls or ACLs and avoid exposing it directly to end users.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ValkeyApplication
Affected:< 7.2.12>= 8.0.0, < 8.0.7>= 8.1.0, < 8.1.6>= 9.0.0, < 9.0.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Valkey version
    Run 'valkey-server --version' or check the package manager for installed Valkey package version
    Affected if Version is earlier than 7.2.12, 8.0.7, 8.1.6, or 9.0.2 (or falls in the ranges <7.2.12, >=8.0.0 <8.0.7, >=8.1.0 <8.1.6, or >=9.0.0 <9.0.2)
  2. Verify if Valkey cluster mode is enabled
    Check configuration file or running process for 'cluster-enabled yes' setting, or run 'valkey-cli cluster info' if cluster is active
    Affected if Cluster mode is enabled and the version is vulnerable
  3. Confirm clusterbus port accessibility
    Review network configuration to determine if the clusterbus port (default 16379) is exposed to untrusted network segments or accessible from outside the trusted environment
    Affected if Clusterbus port is reachable from untrusted networks or external actors
  4. Review clusterbus packet handling logs
    Check Valkey logs for crash events, assertion failures, or out-of-bounds read errors related to clusterbus ping extensions
    Affected if Logs show crashes or errors during clusterbus packet processing

User is affected if running a vulnerable Valkey version with cluster mode enabled and the clusterbus port is accessible to untrusted actors, as the out-of-bounds read can be triggered by malicious clusterbus packets.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 7.2.12 / 8.0.7 / 8.1.6 or later
Fixed in 7.2.128.0.78.1.6
Interim mitigation

Upgrade Valkey to version 9.0.2, 8.1.6, 8.0.7, or 7.2.12 or later. Additionally, restrict network access to the clusterbus port using firewalls or ACLs and avoid exposing it directly to end users.

Recommended fix High confidence

Upgrade to 7.2.12 (for 7.x), 8.0.7 (for 8.0.x), 8.1.6 (for 8.1.x), or 9.0.2 (for 9.0.x) - prefer the latest major version branch that fits your deployment

  1. 1. Identify the currently running Valkey version using `valkey-server --version` or `INFO server` command
  2. 2. Determine which upgrade path applies based on current version (7.x -> 7.2.12, 8.0.x -> 8.0.7, 8.1.x -> 8.1.6, 9.0.x -> 9.0.2)
  3. 3. Schedule a maintenance window for the upgrade
  4. 4. Back up the Valkey data directory and configuration files
  5. 5. Stop the Valkey service
  6. 6. Install the appropriate fixed version (7.2.12, 8.0.7, 8.1.6, or 9.0.2) using the package manager or compilation
  7. 7. Verify the new version is running with `valkey-server --version`
  8. 8. As an additional mitigation, ensure the clusterbus port is not exposed directly to end users and apply network ACLs to restrict access
Caveat Review release notes for any breaking changes between your current version and the target fixed version before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Valkey Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-21863 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data