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.

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: 0.000 (6.6th 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

https://github.com/caddyserver/caddy/security/advisories/GHSA-7r4p-vjf4-gxv4 (x_refsource_CONFIRM)
https://github.com/caddyserver/caddy/issues/6610 (x_refsource_MISC)
https://github.com/caddyserver/caddy/pull/6608 (x_refsource_MISC)
https://github.com/caddyserver/caddy/pull/7545 (x_refsource_MISC)

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.