# CVE-2026-63771: Vrana Adminer cookie injection via X-Forwarded-Prefix header

Source: https://junglewise.ai/threats/cve-2026-63771-vrana-adminer-cookie-injection-via-x-forwarded-prefix-header  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-20. Updated: 2026-07-20  
License: CC BY 4.0 with a link back

CVE-2026-63771 · Severity: high · CVSS 7.1 · Published 2026-07-20

Adminer, a popular web-based database management tool, is vulnerable to a security flaw that allows attackers to manipulate browser cookies. By sending a specially crafted web request through a misconfigured proxy server, an attacker can trick a user's browser into sending sensitive session information to a server controlled by the attacker. This could lead to unauthorized access to the database management interface and the theft of database credentials.

## Quick answers

**Is CVE-2026-63771 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-63771 being exploited in the wild.

**How severe is CVE-2026-63771?** High severity, with a CVSS score of 7.1, published 20 July 2026.

**Which products and versions are affected?** vrana Adminer >= 4.6.0, <= 5.4.2.

**Is there a fix for CVE-2026-63771?** A patch was published on 2026-07-09: Version 5.4.3 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-63771 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-63771?** 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

Adminer versions 4.6.0 through 5.4.2 are vulnerable to cookie attribute injection (CWE-113) because the application unsafely prepends the 'X-Forwarded-Prefix' HTTP header to the 'REQUEST_URI' global variable. This tainted value is subsequently used to manually construct 'Set-Cookie' headers and configure session cookie parameters without sanitizing semicolons or other attribute delimiters. An attacker can exploit this in environments where a reverse proxy forwards client-supplied headers to inject attributes such as 'Domain', 'SameSite=None', or 'Secure'. This can be used to leak the 'adminer_sid' (session ID) and 'adminer_key' (database encryption key) to an attacker-controlled domain or to bypass CSRF protections by downgrading SameSite attributes. The issue is fixed in version 5.4.3 by escaping the REQUEST_URI.

## Affected products

- vrana Adminer >= 4.6.0, <= 5.4.2

## Timeline

- 2026-06-02: disclosed: Vulnerability reported to vendor
- 2026-07-09: patched: Version 5.4.3 released with fix
- 2026-07-20: advisory: NVD publication date

## References

- [https://github.com/vrana/adminer/issues/1298](https://github.com/vrana/adminer/issues/1298)
- [https://github.com/vrana/adminer/releases](https://github.com/vrana/adminer/releases)
- [https://github.com/vrana/adminer/security/advisories/GHSA-c533-9qwm-8w5h](https://github.com/vrana/adminer/security/advisories/GHSA-c533-9qwm-8w5h)
- [https://www.vulncheck.com/advisories/adminer-cookie-injection-via-x-forwarded-prefix-header](https://www.vulncheck.com/advisories/adminer-cookie-injection-via-x-forwarded-prefix-header)