CVE-2026-27623
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk28th percentile - higher than 28% of all known CVEs
Summary
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.
Risk Assessment
An attacker can remotely cause the Valkey server to abort, resulting in service disruption and potential data availability loss for the organization.
Recommendation
Immediately upgrade Valkey to version 9.0.3 or later. As an additional mitigation, isolate Valkey deployments so that only trusted users have access.
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-2026-21863High
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.
- 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. Starting in version 9.0.0 and prior to version 9.0.3, a malicious actor with network access to Valkey can cause the system to abort by triggering an assertion. When processing incoming requests, the Valkey system does not properly reset the networking state after processing an empty request. A malicious actor can then send a request that the server incorrectly identifies as breaking server side invariants, which results in the server shutting down. Version 9.0.3 fixes the issue. As an additional mitigation, properly isolate Valkey deployments so that only trusted users have access.