CVE-2026-21863
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk42th percentile - higher than 42% of all known CVEs
Summary
A vulnerability in Valkey allows an attacker with access to the clusterbus port to send a malformed packet, potentially causing an out-of-bounds read and system crash. The issue stems from missing validation of the ping extension packet location within the buffer.
Risk Assessment
An attacker can trigger a denial of service (DoS) by crashing the system, disrupting key-value store availability and potentially affecting dependent applications.
Recommendation
Immediately upgrade to versions 9.0.2, 8.1.6, 8.0.7, or 7.2.12. Additionally, avoid exposing the cluster bus port directly to end users and protect it with network ACLs.
Other vulnerabilities in Valkey
See all- CVE-2026-63639High
Use-after-free vulnerability in Valkey prior to versions 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1. The RESTORE command accepts a malformed RDB stream that assigns one NACK to multiple consumers, potentially allowing remote code execution.
- CVE-2026-56684High
Valkey, a distributed key-value database, contains a use-after-free vulnerability in the tlsProcessPendingData function. An authenticated client can trigger CLIENT KILL, causing deletion of a node from the list and potentially leading to server crash or remote code execution when TLS is enabled. The issue is fixed in versions 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1.
- CVE-2026-27623High
A vulnerability in Valkey from version 9.0.0 to 9.0.2 allows an attacker with network access to crash the server by sending a specially crafted request. The issue is caused by improper reset of networking state after processing an empty request, leading to an assertion failure and system abort.
- CVE-2025-67733High
A vulnerability in Valkey allows a malicious user to inject arbitrary information into the client response stream via Lua scripts. The issue stems from improper handling of null characters in the Lua script error handling code, potentially corrupting or tampering with data for other users on the same connection.
Original NVD description (English source)
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.