CVE-2026-53550
Description
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.
Statement
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.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | N/A | 5.3 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Red Hat CVSS v3 Score Explanation
Corrected A:H to A:L: all confirmed vulnerable code paths run client-side in the browser (OpenShift Console plugins, Kiali frontend). DoS is limited to freezing the users own browser tab, not server-side denial of service. Aligned with CVEORG rating.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU)
Attackers can create crafted inputs that intentionally cause the regular expression to use excessive backtracking in a way that causes the CPU consumption to spike.
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