CVE-2026-59870
Description
A flaw was found in js-yaml, a JavaScript YAML (YAML Ain't Markup Language) parser. An attacker could exploit this by providing a specially crafted YAML ordered-map document. This could lead to excessive CPU consumption, resulting in a denial of service (DoS) for applications processing the malicious YAML input.
Statement
js-yaml versions 5.0.0 through 5.2.0 are vulnerable to a denial of service via the omapTag.addItem() O(n^2) duplicate-key scan when parsing crafted YAML ordered-map documents with the YAML11_SCHEMA. This affects yaml.load() calls using that schema. Fixed in 5.2.1.
Mitigation
Avoid using the YAML11_SCHEMA when parsing untrusted YAML input, or upgrade to js-yaml 5.2.1 or later. Applications using the default schema (CORE_SCHEMA) are not affected.
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 | 7.5 | 5.3 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: 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:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Frequently Asked Questions
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