CVE-2026-27589
Caddy vulnerable to cross-origin config application via local admin API /load (caddy)
Reported by github_m · Published February 24, 2026
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.
Risk scores
Affected products
| Vendor | Product | Versions |
|---|---|---|
| caddyserver | caddy | < 2.11.1 |
| github.com | caddyserver/caddy/v2 | 0 |
| alpine | caddy | 0, 0 |
| caddyserver | caddy | 0 |
Timeline
- Feb 24, 2026 CVE Published
- Feb 24, 2026 PoC Published (2 in total, the first dated here)
- Feb 25, 2026 EPSS Score (30 in total, the first dated here)
- Feb 27, 2026 CVE Updated
- Mar 17, 2026 Coalition ESS Score (2 in total, the first dated here)
- Mar 17, 2026 Security Advisory
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The same record, from the CLI:
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References
- https://github.com/caddyserver/caddy/security/advisories/GHSA-879p-475x-rqh2 x_refsource_CONFIRM
- https://github.com/caddyserver/caddy/releases/tag/v2.11.1 x_refsource_MISC
- https://github.com/user-attachments/files/25079818/poc.zip x_refsource_MISC
- https://github.com/user-attachments/files/25079820/PR_DESCRIPTION.md x_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-27589 advisory
- https://github.com/advisories/GHSA-879p-475x-rqh2 advisory
- https://github.com/caddyserver/caddy/commit/65e0ddc22137bbbaa68c842ae0b98d0548504545 patch
- https://github.com/caddyserver/caddy url
- https://pkg.go.dev/vuln/GO-2026-4537 url