CVE-2026-540039.1CriticalCWE-454

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

getkirby · kirby

Affected: getkirby kirby · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.7%probability of exploitation in the next 30 days

55th percentile

050100

Higher than 55% of scored CVEs

9.1CriticalCVSS 4.0

LowMediumHighCrit.

DescriptionCVE.org

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 products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

getkirby · kirby< 4.9.4; >= 5.0.0, < 5.4.4

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: External Initialization of Trusted Variables or Data Stores · Misconfiguration and Insecure Design
Vendor: getkirby
Published: July 2026
Band: Unlikely (under 1%), July 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-54003 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.