CSRF in Caddyserver Caddy
CVE-2026-27589
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.
Vulnerability class: CSRF (Cross-Site Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.002 (14.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 14.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.001
Affected products
- Caddyserver Caddy — versions < 2.11.1
Weakness classification (CWE)
References
- github.com/caddyserver/caddy/security/advisories/GHSA-879p-475x-rqh2 (Exploit, Mitigation, Vendor Advisory)
- github.com/caddyserver/caddy/releases/tag/v2.11.1 (Release Notes)
- github.com/user-attachments/files/25079818/poc.zip (Exploit)
- github.com/user-attachments/files/25079820/PR_DESCRIPTION.md (Exploit, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-27589?
- CVE-2026-27589 is a medium-severity vulnerability in Caddyserver Caddy, classified under Cross-Site Request Forgery (CSRF). CVSS score: 6.5/10. Published 2026-02-24.
- How severe is CVE-2026-27589?
- Medium severity. CVSS v3 base score is 6.5 out of 10.