CVE-2026-73643
Description
A flaw was found in js-yaml, a JavaScript YAML parser. A remote attacker could exploit this vulnerability by providing specially crafted YAML input containing nested flow collections. This can lead to exponential parsing time when the application processes untrusted input, consuming excessive CPU resources. This resource exhaustion can block the Node.js event loop and cause a Denial of Service (DoS) for the affected process.
Statement
This is an Important denial-of-service flaw in the js-yaml library, where processing specially crafted YAML input can lead to exponential parsing time. This can cause applications utilizing affected versions of js-yaml within Red Hat products to consume excessive CPU resources, potentially blocking the Node.js event loop and leading to service unavailability.
Mitigation
To mitigate this issue, restrict applications from processing untrusted YAML input with affected versions of the `js-yaml` library. Implement strict input validation to ensure that only trusted and well-formed YAML data is processed. If the application is exposed to external, untrusted sources, consider isolating the application or implementing additional resource limits to prevent complete service disruption.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
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)
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.
Frequently Asked Questions
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