CVE-2026-16434 (GCVE-0-2026-16434)

Vulnerability from cvelistv5 – Published: 2026-08-25 01:29 – Updated: 2026-08-27 14:34
VLAI
Title
Adminer before 5.5.1 X-Forwarded-Prefix Backslash Bypass
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.
Severity
2.3 (Low)
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
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-27 14:31 UTC
CWE
  • CWE-20 - Improper Input Validation
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 6045 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
vrana adminer Affected: 0 , < 5.5.1 (semver)
Unaffected: 5.5.1 (semver)
    cpe:2.3:a:adminer:adminer:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-07-21 00:00
Credits
Infinit3i
Show details on NVD website
To clipboard 

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