CVE-2026-27590 - Vulnerability Analysis

Overview

Caddy < 2.11.1 contains a path confusion vulnerability caused by unsafe FastCGI path splitting logic with Unicode lowercasing, letting attackers cause unintended PHP file execution, exploit requires attacker-controlled file upload.

Severity & Score

Impact

Attackers can execute unintended PHP files, potentially leading to remote code execution depending on deployment.

Mitigation

Update to version 2.11.1 or later.

References

• https://github.com/php/frankenphp/security/advisories/GHSA-g966-83w7-6w38
• https://github.com/caddyserver/caddy/releases/tag/v2.11.1
• https://github.com/caddyserver/caddy/security/advisories/GHSA-5r3v-vc8m-m96g

Social Media Activity(1 post)

TheHackerWire

@thehackerwire

Feb 25, 2026

🔴 CVE-2026-27590 - Critical (9.8) Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's FastCGI path splitting logic computes the split index on a lowercased copy of the request path and then uses that byte index to slice the original pa... 🔗 https://www.thehackerwire.com/vulnerability/CVE-2026-27590/ #CVE #vulnerability #infosec #cybersecurity #security #Tenda #patchstack

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