CVE-2026-52845
8.1 · HIGHOverview
CVE-2026-52845 is a high-severity vulnerability affecting caddyserver caddy. It was published on June 23, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
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 later goes through php_fastcgi, Caddy normalizes HTTP headers into CGI variables by replacing - with _. This lets a client send an underscore alias that survives the forward_auth delete step but becomes the same PHP/FastCGI variable. Result: a remote client can inject or sometimes override identity/group headers trusted by PHP/FastCGI applications behind Caddy. This vulnerability is fixed in 2.11.4.
Remediation
Check the references section for vendor advisories and patches from caddyserver. Update caddy to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| caddyserver | caddy | >= 0, < 2.11.4 | Affected |
References
Frequently Asked Questions
What is CVE-2026-52845?
CVE-2026-52845 is a high-severity vulnerability affecting caddyserver caddy. It was published on June 23, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).
How severe is CVE-2026-52845?
This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-52845?
Check the references section for vendor advisories and patches from caddyserver. Update caddy to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-52845?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-52845 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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