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.
Published: 2026-08-25
Score: 5.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Tue, 25 Aug 2026 02:00:00 +0000

Type Values Removed Values Added
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.
Title Adminer before 5.5.0 Open Redirect via X-Forwarded-Prefix
First Time appeared Adminer
Adminer adminer
Weaknesses CWE-20
CPEs cpe:2.3:a:adminer:adminer:*:*:*:*:*:*:*:*
Vendors & Products Adminer
Adminer adminer
References
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-25T01:29:57.683Z

Reserved: 2026-03-31T17:58:43.753Z

Link: CVE-2026-34959

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-25T02:16:40.400

Modified: 2026-08-25T02:16:40.400

Link: CVE-2026-34959

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses