caddyserver caddy up to 2.11.0 Admin API /load cross-site request forgery

Summaryinfo

A vulnerability was found in caddyserver caddy up to 2.11.0 and classified as problematic. This affects an unknown part of the file /load of the component Admin API. Such manipulation leads to cross-site request forgery. This vulnerability is traded as CVE-2026-27589. The attack may be launched remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in caddyserver caddy up to 2.11.0. It has been rated as problematic. Affected by this issue is an unknown code of the file /load of the component Admin API. The manipulation with an unknown input leads to a cross-site request forgery vulnerability. Using CWE to declare the problem leads to CWE-352. The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request. Impacted is integrity. CVE summarizes:

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, the local caddy admin API (default listen `127.0.0.1:2019`) exposes a state-changing `POST /load` endpoint that replaces the entire running configuration. When origin enforcement is not enabled (`enforce_origin` not configured), the admin endpoint accepts cross-origin requests (e.g., from attacker-controlled web content in a victim browser) and applies an attacker-supplied JSON config. This can change the admin listener settings and alter HTTP server behavior without user intent. Version 2.11.1 contains a fix for the issue.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-27589 since 02/20/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

It is declared as proof-of-concept. The vulnerability scanner Nessus provides a plugin with the ID 299979 (Linux Distros Unpatched Vulnerability : CVE-2026-27589), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.11.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (299979). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• caddyserver

Name

• caddy

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11.0

Website

• Product: https://github.com/caddyserver/caddy/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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