CVE-2026-73643

js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 until 5.2.2, parsing a small YAML document can take exponential time when an application calls load() or loadAll() on untrusted input. In src/parser/parser.ts, readFlowCollection uses restoreState and calls parseNode a second time when a flow-sequence entry is recognized as a key: value pair. If the key is a nested flow sequence of the same shape, every level is parsed twice, causing O(2^n) work and allowing an input under 200 bytes to keep one CPU busy for minutes, block the Node.js event loop, and stall the process. No anchors, aliases, merges, tags, or nondefault options are required. This issue is fixed in version 5.2.2.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/nodeca/js-yaml/commit/3e5240f9cbe645ce5afb58524954a13c8539c853
https://github.com/nodeca/js-yaml/security/advisories/GHSA-pm4m-ph32-ghv5
https://github.com/nodeca/js-yaml/security/advisories/GHSA-pm4m-ph32-ghv5

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-13 18:18

Updated : 2026-08-14 17:20

NVD link : CVE-2026-73643

Mitre link : CVE-2026-73643

CVE.ORG link : CVE-2026-73643

JSON object : View

Products Affected

No product.

CWE

CWE-407

Inefficient Algorithmic Complexity

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