CVE-2026-56704: Adminer before 5.4.3 Cross-Site Scripting via MySQL Version String

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-25 · updated 2026-10-12
Weakness: CWE-79

Description

Adminer before 5.4.3 inserts unsanitized database server version strings into script tags with valid CSP nonces without proper validation. Attackers controlling a rogue MySQL server can return crafted version strings that break out of the JavaScript context and execute arbitrary code, bypassing Content Security Policy protections.

Affected products

vrana adminer: before 5.4.3 — fixed in 5.4.3

How to fix

Upgrade to a fixed version: vrana adminer 5.4.3. Check the vendor advisory for mitigations.

References

https://github.com/vrana/adminer/security/advisories/GHSA-h6jr-7pr6-grgj
https://www.vulncheck.com/advisories/adminer-before-cross-site-scripting-via-mysql-version-string

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