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Vulnerabilities / CVE-2026-27590

critical

CVE-2026-27590

Caddy is an extensible server platform that uses TLS by default. Prior ...

Published Modified CWE 20, 180
In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GHSA8.9CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

Trivy's own label is CRITICAL. Rated critical by NVD. Rated lower by GHSA (high).

Description

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.

Affected packages and fixed versions

SourcePackageFixed in
alpine 3.23caddy2.11.2-r0
alpine 3.24caddy2.11.1-r0
alpine edgecaddy2.11.1-r0
debian 12caddy2.6.2-5+deb12u1
debian 13caddy2.6.2-12+deb13u1
debian 14caddy2.11.2-1
echocaddy2.6.2-5+deb12u1
go::GitHub Security Advisory Gogithub.com/caddyserver/caddy/v22.11.1
minimoscaddy2.11.1-r0
rapidfort alpine 3.20caddy2.11.1-r0
rapidfort alpine 3.21caddy2.11.1-r0
rapidfort alpine 3.22caddy2.11.1-r0
Show all 20 entries from 20 sources
SourcePackageFixed in
alpine 3.23caddy2.11.2-r0
alpine 3.24caddy2.11.1-r0
alpine edgecaddy2.11.1-r0
debian 12caddy2.6.2-5+deb12u1
debian 13caddy2.6.2-12+deb13u1
debian 14caddy2.11.2-1
echocaddy2.6.2-5+deb12u1
go::GitHub Security Advisory Gogithub.com/caddyserver/caddy/v22.11.1
minimoscaddy2.11.1-r0
rapidfort alpine 3.20caddy2.11.1-r0
rapidfort alpine 3.21caddy2.11.1-r0
rapidfort alpine 3.22caddy2.11.1-r0
rapidfort alpine 3.23caddy2.11.1-r0
rapidfort debian 12caddy0:2.11.2-1, 0:2.6.2-12+deb13u1, 0:2.6.2-5+deb12u1
rapidfort debian 13caddy0:2.11.2-1, 0:2.6.2-12+deb13u1, 0:2.6.2-5+deb12u1
rapidfort fedora 43caddy2.10.2-9.fc43
rapidfort Oracle Linux 10caddy2.10.2-9.el10_3
rapidfort ubuntu 20.04caddy0:2.11.2-1
rapidfort ubuntu 22.04caddy0:2.11.2-1
rapidfort ubuntu 24.04caddy0:2.11.2-1

References

Vulnerability data compiled from the Trivy vulnerability database (trivy-db, Aqua Security, Apache License 2.0), which aggregates third-party advisories. CVE records are published by The MITRE Corporation under the CVE Terms of Use; CVE is a trademark of MITRE. This product uses data from the NVD API but is not endorsed or certified by the NVD. Severity, titles and advisory data from the GitHub Advisory Database (CC BY 4.0), Red Hat security data (CC BY 4.0) and the other sources linked on each entry. Entries may be summarised or re-formatted; the linked original is the authoritative record.