Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Caddyserver | Caddy | < 2.11.1 |
Related Weaknesses (CWE)
References
- https://github.com/caddyserver/caddy/releases/tag/v2.11.1Release Notes
- https://github.com/caddyserver/caddy/security/advisories/GHSA-879p-475x-rqh2ExploitMitigationVendor Advisory
- https://github.com/user-attachments/files/25079818/poc.zipExploit
- https://github.com/user-attachments/files/25079820/PR_DESCRIPTION.mdExploitThird Party Advisory
FAQ
What is CVE-2026-27589?
CVE-2026-27589 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 tha...
How severe is CVE-2026-27589?
CVE-2026-27589 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-27589?
Check the references section above for vendor advisories and patch information. Affected products include: Caddyserver Caddy.