Caddy: Unsafe Unicode Handling in FastCGI splitPos Allows Execution of Non-PHP Files (CVE-2026-45135) | HOL Guard CVE

High · CVSS 8.1CVE-2026-45135

Caddy: Unsafe Unicode Handling in FastCGI splitPos Allows Execution of Non-PHP Files

Answer in brief

CVE-2026-45135 records a High severity (CVSS 8.1) vulnerability in Caddy: Unsafe Unicode Handling in FastCGI splitPos Allows Execution of Non-PHP Files. The current sources do not mark it as known exploited. The current feed maps caddyserver/caddy (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jun 23, 2026Updated Jun 26, 2026Source checked Sep 19, 2026First seen by HOL Jun 23, 2026Material review Jun 26, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.1
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 8.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps caddyserver/caddy (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
caddyserver/caddygeneric	>= 2.7.0, < 2.11.3	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for caddyserver/caddy.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Jun 23, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Jun 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jun 23, 2026

Sources and claim methodology

GitHub security advisorygithub.com

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.