Auth bypass in Caddyserver Caddy
CVE-2026-30851
Caddy is an extensible server platform that uses TLS by default. From version 2.10.0 to before version 2.11.2, forward_auth copy_headers does not strip client-supplied headers, allowing identity injection and privilege escalation. This iss…
Vulnerability class: Broken Authentication
EPSS: 0.002 (16.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.
Affected products
- Caddyserver Caddy — versions >= 2.10.0, < 2.11.2
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Patch, Mitigation, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
Frequently asked questions
- What is CVE-2026-30851?
- CVE-2026-30851 is a high-severity vulnerability in Caddyserver Caddy, classified under Improper Authentication. CVSS score: 8.1/10. Published 2026-03-07.
- How severe is CVE-2026-30851?
- High severity. CVSS v3 base score is 8.1 out of 10.