Kirby: External Initialization of the Panel on reverse proxy setups with the `Forwarded` header

published 2026-06-18 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-42666 , GHSA-whxw-24jc-cwmv

cvss: 9.1; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.7%; EPSS 0.7% chance of exploitation in 30 days, percentile 54%
public exploits: 0; none known

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.

Patch / fix

fixed in 3 links 7

packagist getkirby/cms 4.9.4, 5.4.4
getkirby kirby 4.9.4, 5.4.4
getkirby panel 4.9.4, 5.4.4

github.com/getkirby/kirby@1c7fee9 commit
github.com/getkirby/kirby@3423f66 commit
github.com/getkirby/kirby@66a3a14 commit
github.com/getkirby/kirby@ab992dc commit
github.com/getkirby/kirby#8166 pull request
github.com/getkirby/kirby/releases/tag/4.9.4 release
github.com/getkirby/kirby/releases/tag/5.4.4 release

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 4 mo ago (2026-07-09)

Exploit prediction

0.74% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	9.1	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
CNA	4.0	9.1	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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem	package	affected	fixed in
packagist	getkirby/cms	<4.9.4 >=5.0.0-alpha.1, <5.4.4	4.9.4 5.4.4

Affected products

getkirby kirby

Classification

Weakness

CWE-454 External Initialization of Trusted Variables or Data Stores

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary