CVE-2026-59870
MEDIUMjs-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing
Title source: cnaDescription
js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.1, YAML11_SCHEMA support for the !!omap tag in src/tag/sequence/omap.ts uses omapTag.addItem() to perform a linear duplicate-key scan on every insertion, causing O(n^2) CPU consumption when yaml.load() parses a crafted ordered-map document. This issue is fixed in version 5.2.1.
References (3)
Core 3
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm
X_Refsource_Misc x_refsource_misc
https://github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe
X_Refsource_Misc x_refsource_misc
https://github.com/nodeca/js-yaml/releases/tag/5.2.1
Scores
CVSS v3
5.3
EPSS
0.0041
EPSS Percentile
33.7%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-407
CWE-770
Status
published
Products (3)
nodeca/js-yaml
5.0.0 - 5.2.1
nodeca/js-yaml
>= 5.0.0, < 5.2.1
npm/js-yaml
5.0.0 - 5.2.1npm
Published
Jul 08, 2026
Tracked Since
Jul 08, 2026