SEPTEMBER 18, 2026
Live Feed
Back to database
Case File

CVE-2026-84375

HIGH · CVSS 7.5 EPSS 0.39% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-01 · Last synced 2026-09-18

CyberRota Analysis

AI-Generated

The js-yaml library, used for parsing and dumping YAML in JavaScript, is vulnerable to a denial-of-service attack due to improper handling of empty mappings during merge key processing, leading to excessive CPU consumption. This vulnerability can be exploited by attackers to create small YAML documents that cause significant resource strain on applications that parse untrusted YAML, particularly where merge processing is enabled by default. Organizations utilizing affected versions (3.0.0 to 3.15.2 and 4.3.2) should prioritize upgrading to the patched versions (3.15.2 and 4.3.2) to mitigate potential service disruptions.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-84375
Severity
HIGH
CVSS
7.5
EPSS
0.39%
Java

Original NVD Description

js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2 and 4.3.2, maxTotalMergeKeys in lib/js-yaml/loader.js and lib/loader.js does not count empty mapping sources while processing the merge key <<. An attacker can alias a large sequence of empty mappings into many merge targets, causing O(N * K) processing while totalMergeKeys remains unchanged and the configured resource limit is never reached. A relatively small YAML document can therefore cause prolonged CPU consumption in applications that parse untrusted YAML, and merge processing is enabled by default on these release lines. This issue is fixed in versions 3.15.2 and 4.3.2.