What is CVE-2026-52845?

CVE-2026-52845 is a high-severity vulnerability in Caddyserver Caddy, classified under Improper Authentication. CVSS score: 8.1/10. Published 2026-06-23.

How severe is CVE-2026-52845?

High severity. CVSS v3 base score is 8.1 out of 10.

Auth bypass in Caddyserver Caddy

CVE-2026-52845

Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, forward_auth copy_headers deletes the exact client-supplied identity header before copying the trusted value from the auth gateway. But when the request late…

Vulnerability class: Broken Authentication

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 < 2.11.4

Weakness classification (CWE)

CWE-287 — Improper Authentication
CWE-290 — Authentication Bypass by Spoofing
CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

References

security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-52845?: CVE-2026-52845 is a high-severity vulnerability in Caddyserver Caddy, classified under Improper Authentication. CVSS score: 8.1/10. Published 2026-06-23.
How severe is CVE-2026-52845?: High severity. CVSS v3 base score is 8.1 out of 10.