What’s Vulnerable › Vulnerabilities

CVE-2026-34959: Adminer before 5.5.0 Open Redirect via X-Forwarded-Prefix

• Severity: medium (CVSS 4.7 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-20

Description

Adminer 4.6.0 before 5.5.0 prepends the client-supplied X-Forwarded-Prefix header to $_SERVER["REQUEST_URI"] with no trusted-proxy check and no validation of the prefix value. An attacker can supply an absolute URL (e.g. X-Forwarded-Prefix: https://evil.example) that flows into Location redirect headers, the Set-Cookie path attribute, and self-referential links. This enables an authenticated open redirect after state-changing POSTs, unauthenticated control of the session cookie path attribute, and poisoning of self-referential links; CR/LF cannot be injected, so header splitting/XSS is not possible.

Affected products

• vrana adminer: before 5.5.0 — fixed in 5.5.0

How to fix

Upgrade to a fixed version: vrana adminer 5.5.0. Check the vendor advisory for mitigations.

References

• https://github.com/vrana/adminer/security/advisories/GHSA-8478-xrj3-h9c2
• https://www.vulncheck.com/advisories/adminer-before-open-redirect-via-x-forwarded-prefix
• https://github.com/vrana/adminer/security/advisories/GHSA-8478-xrj3-h9c2

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