HTTP Response Splitting Affecting getkirby/cms package, versions <4.9.4>=5.0.0-alpha.1, <5.4.4
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PHP-GETKIRBYCMS-17423220
- published23 Jun 2026
- disclosed18 Jun 2026
- creditUnknown
Introduced: 18 Jun 2026
CVE-2026-50188 (opens in a new tab)How to fix?
Upgrade getkirby/cms to version 4.9.4, 5.4.4 or higher.
Overview
Affected versions of this package are vulnerable to HTTP Response Splitting via the headers option in the Remote process. An attacker can inject or override HTTP headers in outgoing requests by including newline characters in user-controlled input that is forwarded to the header value. This is only exploitable if custom code, plugins, or integrations pass untrusted input into the headers option of outgoing HTTP requests.