CVE-2026-53550

A flaw was found in js-yaml, a JavaScript YAML parser and dumper. A remote attacker can exploit this vulnerability by providing a specially crafted YAML document that repeatedly uses the same alias in a merge sequence. This can lead to algorithmic CPU exhaustion, causing the Node.js worker or event loop to be blocked for an extended period, resulting in a denial of service (DoS) for the affected system.

Red Hat rates this flaw as Moderate impact, consistent with the upstream CVEORG assessment. The vulnerability causes CPU exhaustion via quadratic merge-key processing in js-yaml's YAML parser. In Red Hat products, all confirmed vulnerable code paths run client-side in the browser (OpenShift Console plugins, Kiali frontend, monitoring dashboard editors). A denial of service is limited to freezing the user's own browser tab when processing crafted YAML input, not server-side resource exhaustion. The user can recover by closing the tab.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.