Kirby: Request header injection in `Http\Remote`

published 2026-06-18 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-42669 , GHSA-4v4h-m2qq-ppgw

cvss: 6.9; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits: 0; none known

Kirby is an open-source content management system. Prior to 4.9.4 and 5.4.4, Kirby sites and plugins using the Kirby Http Remote class, including Remote::request(), Remote::get(), and Remote::post(), to send outgoing HTTP requests with untrusted data in the headers option could allow newline characters in a header value to inject a separate unintended request header to the remote service. This issue is fixed in versions 4.9.4 and 5.4.4.

Patch / fix

fixed in 3 links 4

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@aa33414 commit
github.com/getkirby/kirby@fad9cbd commit
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: no
Technical impact: partial
Assessed: 4 mo ago (2026-07-09)

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA:N
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/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-93 Improper Neutralization of CRLF Sequences
CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers

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