Vulnerability Details CVE-2026-45135
Caddy is an extensible server platform that uses TLS by default. From 2.7.0 until 2.11.3, the FastCGI transport's splitPos() in modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go misuses golang.org/x/text/search with search.IgnoreCase when the request path contains a non-ASCII byte. Two distinct flaws in that fallback let an attacker mislead Caddy's FastCGI splitting into treating a non-.php (or other configured split_path extension) file as a script. In any deployment where the attacker can place content into a file served via FastCGI (uploads, file storage, etc.), this can be escalated to remote code execution by crafting a URL whose path triggers either flaw. This vulnerability is fixed in 2.11.3.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.004
EPSS Ranking 31.7%
CVSS Severity
CVSS v3 Score 8.1
References
Products affected by CVE-2026-45135
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cpe:2.3:a:caddyserver:caddy:2.10.0
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cpe:2.3:a:caddyserver:caddy:2.10.1
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cpe:2.3:a:caddyserver:caddy:2.10.2
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cpe:2.3:a:caddyserver:caddy:2.11.0
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cpe:2.3:a:caddyserver:caddy:2.11.1
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cpe:2.3:a:caddyserver:caddy:2.11.2
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cpe:2.3:a:caddyserver:caddy:2.7.0
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cpe:2.3:a:caddyserver:caddy:2.7.1
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cpe:2.3:a:caddyserver:caddy:2.7.2
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cpe:2.3:a:caddyserver:caddy:2.7.3
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cpe:2.3:a:caddyserver:caddy:2.7.4
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cpe:2.3:a:caddyserver:caddy:2.7.5
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cpe:2.3:a:caddyserver:caddy:2.7.6
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cpe:2.3:a:caddyserver:caddy:2.8.0
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cpe:2.3:a:caddyserver:caddy:2.8.1
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cpe:2.3:a:caddyserver:caddy:2.8.2
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cpe:2.3:a:caddyserver:caddy:2.8.3
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cpe:2.3:a:caddyserver:caddy:2.8.4
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cpe:2.3:a:caddyserver:caddy:2.9.0
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cpe:2.3:a:caddyserver:caddy:2.9.1