Is CVE-2026-34959 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-34959 being exploited in the wild.

How severe is CVE-2026-34959?

Medium severity, with a CVSS score of 4.7, published 25 August 2026.

Is there a fix for CVE-2026-34959?

A patch was published on 2026: Fixed in version 5.5.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-34959 attacked?

It is attacked over the network.

Am I affected by CVE-2026-34959?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-34959: Adminer X-Forwarded-Prefix open redirect and cookie path hijacking

CVE-2026-34959 · Severity: medium · CVSS 4.7 · Published 2026-08-25

Adminer, a popular database management tool, unsafely processes the X-Forwarded-Prefix HTTP header without validating the proxy source or prefix value. An attacker can inject an absolute URL into this header to redirect users to attacker-controlled sites after performing database operations, manipulate session cookie scope, or poison self-referential links in the application. While existing authentication prevents the most direct attacks, this creates an open redirect vulnerability and enables session hijacking risks on shared hosting environments.

Quick answers

Is CVE-2026-34959 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-34959 being exploited in the wild.
How severe is CVE-2026-34959?: Medium severity, with a CVSS score of 4.7, published 25 August 2026.
Which products and versions are affected?: Vrana Adminer 4.6.0 to 5.4.4.
Is there a fix for CVE-2026-34959?: A patch was published on 2026: Fixed in version 5.5.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-34959 attacked?: It is attacked over the network.
Am I affected by CVE-2026-34959?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability lies in Adminer's reverse-proxy support (bootstrap.inc.php:40-42), which blindly prepends the client-supplied X-Forwarded-Prefix header to $_SERVER["REQUEST_URI"] with no validation or trusted-proxy checking. Because REQUEST_URI always begins with "/", an attacker-supplied prefix like "https://evil.example" creates an absolute URL that flows into three sinks: Location redirect headers (used in db.inc.php, edit.inc.php), the Set-Cookie path attribute via cookie_path() function, and self-referential links. The attack requires network access (spoofable header) but triggers different impacts: authenticated users performing state-changing POSTs (table operations) receive open-redirect responses; unauthenticated attackers can control the session cookie path attribute to enable session-fixation attacks on shared hosts; all users see poisoned self-referential URLs. CR/LF injection is blocked by PHP's header() function, preventing header splitting or XSS. Patched in version 5.5.0.

Affected products

Vrana Adminer 4.6.0 to 5.4.4

Timeline

2026-07-17: disclosed: GHSA-8478-xrj3-h9c2 published on GitHub
2026-08-25: other: CVE-2026-34959 published on NVD
2026: patched: Fixed in version 5.5.0

References

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