UBUNTU-CVE-2026-30852

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Source
https://ubuntu.com/security/CVE-2026-30852
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-30852.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-30852
Upstream
Published
2026-03-07T17:15:00Z
Modified
2026-03-25T19:48:39.092281Z
Severity
  • 5.5 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P CVSS Calculator
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Caddy is an extensible server platform that uses TLS by default. From version 2.7.5 to before version 2.11.2, the varsregexp matcher in vars.go:337 double-expands user-controlled input through the Caddy replacer. When varsregexp matches against a placeholder like {http.request.header.X-Input}, the header value gets resolved once (expected), then passed through repl.ReplaceAll() again (the bug). This means an attacker can put {env.DATABASE_URL} or {file./etc/passwd} in a request header and the server will evaluate it, leaking environment variables, file contents, and system info. This issue has been patched in version 2.11.2.

References

Affected packages

Ubuntu:Pro:24.04:LTS / caddy

Package

Name
caddy
Purl
pkg:deb/ubuntu/caddy@2.6.2-6ubuntu0.24.04.3+esm2?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
2.6.2-6ubuntu0.24.04.3+esm2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "caddy",
            "binary_version": "2.6.2-6ubuntu0.24.04.3+esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-30852.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_name": "caddy",
            "binary_version": "2.6.2-12"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-30852.json"