CVE-2026-59868
js-yaml: YAML merge-key chains can force quadratic CPU consumption
Description
js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.0, when merge keys are enabled, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in version 5.2.0.
INFO
Published Date :
July 8, 2026, 4:16 p.m.
Last Modified :
July 13, 2026, 3:06 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update js-yaml to version 5.2.0 or later.
- Ensure merge keys are disabled if not required.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-59868.
| URL | Resource |
|---|---|
| https://github.com/nodeca/js-yaml/commit/3105455b81dee69e0fd36e09ac0b2ccfdb54adc1 | Patch |
| https://github.com/nodeca/js-yaml/releases/tag/5.2.0 | Release Notes |
| https://github.com/nodeca/js-yaml/security/advisories/GHSA-g796-fgmg-93mv | Exploit Vendor Advisory |
| https://github.com/nodeca/js-yaml/security/advisories/GHSA-g796-fgmg-93mv | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-59868 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-59868
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-59868 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-59868 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 13, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-770 Added CPE Configuration OR *cpe:2.3:a:nodeca:js-yaml:*:*:*:*:*:node.js:*:* versions from (including) 5.0.0 up to (excluding) 5.2.0 Added Reference Type GitHub, Inc.: https://github.com/nodeca/js-yaml/commit/3105455b81dee69e0fd36e09ac0b2ccfdb54adc1 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/nodeca/js-yaml/releases/tag/5.2.0 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/nodeca/js-yaml/security/advisories/GHSA-g796-fgmg-93mv Types: Exploit, Vendor Advisory Added Reference Type CISA-ADP: https://github.com/nodeca/js-yaml/security/advisories/GHSA-g796-fgmg-93mv Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 09, 2026
Action Type Old Value New Value Added Reference https://github.com/nodeca/js-yaml/security/advisories/GHSA-g796-fgmg-93mv Added SSVC {'id': 'CVE-2026-59868', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-09T13:41:56.104624Z'} -
New CVE Received by [email protected]
Jul. 08, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'nodeca', 'product': 'js-yaml', 'versions': [{'status': 'affected', 'version': '>= 5.0.0, < 5.2.0'}]}] Added Description js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.0, when merge keys are enabled, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in version 5.2.0. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-407 Added Reference https://github.com/nodeca/js-yaml/commit/3105455b81dee69e0fd36e09ac0b2ccfdb54adc1 Added Reference https://github.com/nodeca/js-yaml/releases/tag/5.2.0 Added Reference https://github.com/nodeca/js-yaml/security/advisories/GHSA-g796-fgmg-93mv