CVE-2026-16434

NameCVE-2026-16434
DescriptionAdminer 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
adminer (PTS)bullseye4.7.9-2vulnerable
bookworm4.8.1-1vulnerable
trixie5.2.1+dfsg-1vulnerable
forky, sid6.0.0-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
adminersource(unstable)6.0.0-1

Notes

https://github.com/vrana/adminer/security/advisories/GHSA-fr74-9mf9-gf44

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