DEBIAN-CVE-2026-27590
Record from OSV · Published February 24, 2026
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 path. This is unsafe for Unicode because `strings.ToLower()` can change UTF-8 byte length for some characters. As a result, Caddy can derive an incorrect `SCRIPT_NAME`/`SCRIPT_FILENAME` and `PATH_INFO`, potentially causing a request that contains `.php` to execute a different on-disk file than intended (path confusion). In setups where an attacker can control file contents (e.g., upload features), this can lead to unintended PHP execution of non-.php files (potential RCE depending on deployment). Version 2.11.1 fixes the issue.
Fixed versions
Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.
| Package | Ecosystem | Fixed in |
|---|---|---|
| caddy | Debian:12 | 2.6.2-5+deb12u1 |
| caddy | Debian:13 | 2.6.2-12+deb13u1 |
| caddy | Debian:14 | 2.11.2-1 |
Risk scores
Affected products
| Vendor | Product | Versions |
|---|---|---|
| Debian:12 | caddy | 2.6.2-5, 0 |
| Debian:13 | caddy | 0, 2.6.2-12 |
| Debian:14 | caddy | 2.6.2-12, 2.6.2-13, 2.6.2-14 |
Timeline
- Feb 24, 2026 CVE Published
- Oct 24, 2026 CVE Updated
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