Log in Start free

Vulnerability · Published Jul 9, 2026 · Assigned by GitHub_M

CVE-2026-54003Kirby: External Initialization of the Panel on reverse proxy setups with the `Forwarded` header

Critical 9.1

In plain English

A critical-severity security flaw in kirby from getkirby. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 55% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)9.1Critical
Exploit odds (30 days)0.7%top 45.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Kirby is an open-source content management system. Prior to 4.9.4 and from 5.4.4, Kirby sites with no configured user accounts that run on publicly accessible servers behind a reverse proxy setting the Forwarded, X-Client-IP, or X-Real-IP request header could allow remote attackers to install the Panel and create the first admin user because local-IP checks trusted those headers incorrectly. This issue is fixed in versions 4.9.4 and 5.4.4.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Packagistgetkirby/cms4.9.4GHSA-whxw-24jc-cwmv
Packagistgetkirby/cms5.4.4GHSA-whxw-24jc-cwmv

Affected products (as reported)

VendorProductVersions
getkirby kirby < 4.9.4>= 5.0.0, < 5.4.4

Weakness: CWE-454 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References