UBUNTU-CVE-2026-27590

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Source
https://ubuntu.com/security/CVE-2026-27590
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27590.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-27590
Upstream
Published
2026-02-24T17:29:00Z
Modified
2026-02-28T06:17:46.861080Z
Severity
  • 8.9 (High) CVSS_V4 - CVSS: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 CVSS Calculator
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:Pro:24.04:LTS / caddy

Package

Name
caddy
Purl
pkg:deb/ubuntu/caddy@2.6.2-6ubuntu0.24.04.3+esm1?arch=source&distro=esm-apps/noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.6.2-6
2.6.2-6ubuntu0.24.04.1
2.6.2-6ubuntu0.24.04.2
2.6.2-6ubuntu0.24.04.2+esm1
2.6.2-6ubuntu0.24.04.3
2.6.2-6ubuntu0.24.04.3+esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.6.2-6ubuntu0.24.04.3+esm1",
            "binary_name": "caddy"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27590.json"

Ubuntu:25.10 / caddy

Package

Name
caddy
Purl
pkg:deb/ubuntu/caddy@2.6.2-12?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.6.2-9
2.6.2-11
2.6.2-12

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.6.2-12",
            "binary_name": "caddy"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27590.json"