CVE-2026-27623 | Valkey has Pre-Authentication DOS from malformed RESP request

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.

Published: 2026-02-23 Last update: 2026-02-25 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-27623 is rated Low Risk (36.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.06%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-27623

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-02-24 — 0.06% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-27623

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-27623

OS Trackers for CVE-2026-27623

vendor priority summary link
alpine — CVE-2026-27623: 1 source package rows (valkey); 5 state rows across 2 repos (3.23-main, edge-main); fixed 2, open 3. https://security.alpinelinux.org/vuln/CVE-2026-27623
debian unimportant CVE-2026-27623 unimportant priority: Debian including 1 source packages (valkey), 3 status rows across 3 suites (forky, sid, trixie): resolved 3. https://security-tracker.debian.org/tracker/CVE-2026-27623
redhat high — https://access.redhat.com/security/cve/CVE-2026-27623
suse high — https://www.suse.com/security/cve/CVE-2026-27623/
ubuntu medium CVE-2026-27623 medium priority: Ubuntu including 1 source packages (valkey), 4 status rows across 4 suites (jammy, noble, questing, upstream): not-affected 2, DNE 1, needs-triage 1. https://ubuntu.com/security/CVE-2026-27623

Affected software / configurations for CVE-2026-27623

Vendor Product Version Raw CPE
lfprojects valkey >= 9.0.0, < 9.0.3 cpe:2.3:a:lfprojects:valkey:*:*:*:*:*:*:*:*

References for CVE-2026-27623

cvelogic Threat Intelligence