Skip to main content

Uncontrolled Resource Consumption in js-yaml

CVE-2026-84375

  • js-yaml
High
7.5/10

Summary

js-yaml is a JavaScript YAML parser and dumper. In versions 3.0.0 prior to 3.15.2 and 4.x prior to 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.

  • LOW
  • NETWORK
  • NONE
  • UNCHANGED
  • NONE
  • NONE
  • NONE
  • HIGH

CWE-400 - Uncontrolled resource consumption

An uncontrolled resource allocation attack (also known as resource exhaustion attack) triggers unauthorized overconsumption of the limited resources in an application, such as memory, file system storage, database connection pool entries, and CPU. This may lead to denial of service for valid users and degradation of the application's functionality as well as that of the host operating system.

References

Advisory Timeline

  • Published