CVE-2026-16434
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Summary
Adminer 4.6.0 through 5.5.0 (fixed in 5.5.1) contains an incomplete fix for a prior X-Forwarded-Prefix vulnerability (GHSA-8478-xrj3-h9c2). The validation guard (bootstrap.inc.php) only rejects prefixes matching ^/[^/], blocking //evil.com but allowing values such as /\evil.com whose second character is a backslash. Because browsers normalize backslash to forward slash, a network-path reference survives into REQUEST_URI and reaches cookie_path(), affecting the Set-Cookie Path attribute. Exploitation requires that clients can set the X-Forwarded-Prefix header (a misconfigured or absent reverse proxy). Impact is limited to anomalous cookie-path scoping.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| vrana | adminer | 0 < 5.5.1 | affected |
| vrana | adminer | 5.5.1 | unaffected |
Weaknesses
- CWE-20: Improper Input Validation
References
- https://github.com/vrana/adminer/security/advisories/GHSA-fr74-9mf9-gf44
- https://www.vulncheck.com/advisories/adminer-before-x-forwarded-prefix-backslash-bypass
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