High severity · published Feb 23, 2026
CVE-2026-27623
Valkey has Pre-Authentication DOS from malformed RESP request
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 35% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
VA
valkey · valkey-io
>= 9.0.0, < 9.0.3 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27623
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-27623
Vendor Advisory
https://github.com/valkey-io/valkey/security/advisories/GHSA-93p9-5vc7-8wgr
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-27623
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2442021
security.access.redhat.com
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27623.json
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