CVE-2026-59869
Description
A flaw was found in js-yaml, a JavaScript YAML parser and dumper. A remote attacker could exploit this vulnerability by providing a specially crafted YAML document containing a chain of mappings with merge keys. This could cause the parser to consume excessive CPU resources, leading to a Denial of Service (DoS) for the affected system.
Statement
This vulnerability is rated as Important. Red Hat products utilizing js-yaml to process untrusted YAML input are susceptible to a denial of service, as a remote attacker can provide a crafted document that consumes excessive CPU resources. This is considered Important due to the potential for service disruption without requiring authentication or complex attack vectors.
Mitigation
To reduce exposure, restrict the processing of untrusted YAML documents by applications that rely on `js-yaml`. Implement robust input validation and sanitization for all YAML data originating from external or untrusted sources. Consider limiting network access to services that parse YAML content to trusted networks or clients through appropriate firewall configurations.
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 | 7.5 | N/A | 7.5 |
| 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 | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU)
Frequently Asked Questions
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