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 issue has been patched in version 2.11.2.
Vulnerability class: Broken Authentication
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.004 (28.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.3% 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: 0.004 · change: +0.001
Affected products
- Caddyserver Caddy — versions >= 2.10.0, < 2.11.2
Weakness classification (CWE)
References
- github.com/caddyserver/caddy/security/advisories/GHSA-7r4p-vjf4-gxv4 (Exploit, Patch, Mitigation, Vendor Advisory)
- github.com/caddyserver/caddy/issues/6610 (Issue Tracking)
- github.com/caddyserver/caddy/pull/6608 (Patch, Issue Tracking)
- github.com/caddyserver/caddy/pull/7545 (Patch, 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.