CVE-2026-45135
Caddy: Unsafe Unicode Handling in FastCGI splitPos Allows Execution of Non-PHP Files
Description
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.
How to fix CVE-2026-45135
To remediate CVE-2026-45135, upgrade the affected package to a fixed version below.
- —upgrade to 2.11.3 or later
Is CVE-2026-45135 being exploited?
Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 2.7.0, < 2.11.3
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |