CVE-2026-21863: CWE-125: Out-of-bounds Read in valkey-io valkey
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.
AI Analysis
Technical Summary
Valkey's clusterbus packet processing code does not validate that a clusterbus ping extension packet is within the buffer before reading it, leading to an out-of-bounds read vulnerability (CWE-125). This can be triggered by sending an invalid packet to the clusterbus port, potentially causing a denial of service via system crash. The vulnerability affects Valkey versions prior to 9.0.2, 8.1.6, 8.0.7, and 7.2.12. The issue is addressed in these fixed versions. The vendor advisory from Red Hat confirms the vulnerability and provides updated packages to remediate the issue.
Potential Impact
The vulnerability allows an unauthenticated attacker with network access to the Valkey clusterbus port to cause a denial of service by crashing the system through an out-of-bounds read. There is no indication of confidentiality or integrity impact. The CVSS v3.1 base score is 7.5 (High), reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability.
Mitigation Recommendations
Fixed versions 9.0.2, 8.1.6, 8.0.7, and 7.2.12 of Valkey are available and should be applied to remediate this vulnerability. Additionally, it is recommended to not expose the clusterbus connection directly to end users and to protect this connection with dedicated network ACLs. The vendor advisory from Red Hat provides updated packages and instructions for applying the fix. Patch status is confirmed by the vendor advisory and official fixes are available.
CVE-2026-21863: CWE-125: Out-of-bounds Read in valkey-io valkey
Description
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.
CVSS v3.1
Score 7.5high
Affected software
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Valkey's clusterbus packet processing code does not validate that a clusterbus ping extension packet is within the buffer before reading it, leading to an out-of-bounds read vulnerability (CWE-125). This can be triggered by sending an invalid packet to the clusterbus port, potentially causing a denial of service via system crash. The vulnerability affects Valkey versions prior to 9.0.2, 8.1.6, 8.0.7, and 7.2.12. The issue is addressed in these fixed versions. The vendor advisory from Red Hat confirms the vulnerability and provides updated packages to remediate the issue.
Potential Impact
The vulnerability allows an unauthenticated attacker with network access to the Valkey clusterbus port to cause a denial of service by crashing the system through an out-of-bounds read. There is no indication of confidentiality or integrity impact. The CVSS v3.1 base score is 7.5 (High), reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability.
Mitigation Recommendations
Fixed versions 9.0.2, 8.1.6, 8.0.7, and 7.2.12 of Valkey are available and should be applied to remediate this vulnerability. Additionally, it is recommended to not expose the clusterbus connection directly to end users and to protect this connection with dedicated network ACLs. The vendor advisory from Red Hat provides updated packages and instructions for applying the fix. Patch status is confirmed by the vendor advisory and official fixes are available.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-01-05T16:44:16.367Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-21863","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:5445","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3443","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3507","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:8753","vendor":"Red Hat"}]
Threat ID: 699cbd8cbe58cf853bc4b3eb
Added to database: 02/23/2026, 20:50:20 UTC
Last enriched: 07/15/2026, 08:32:38 UTC
Last updated: 07/31/2026, 19:22:57 UTC
Views: 185
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.