CVE-2026-71429
CVE-2026-71429
stream-json is a micro-library of stream components for processing JSON and JSONC with a minimal memory footprint. Prior to 3.5.0, the path filters pick, ignore, filter, and replace in src/core/filters/filter-base.js recompute the full path string from the nesting stack for every checkable token. Because the stack length equals the current nesting depth and a checkable token is emitted at every level, a depth D document costs O(D²) rather than O(D) to process. The issue is triggered by nesting depth rather than byte volume, including the documented pick({filter: 'data'}) traversal-until-match path, so an application that sends untrusted JSON through a string or RegExp filter can block the Node.js event loop and cause denial of service with a small deeply nested document. The streamArray, streamObject, and streamValues streamers are not affected because they use the constant-time asm.depth getter. This issue is fixed in version 3.5.0.
CVSS v3 metric
CVSS v3 base score 6.2 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-71429?
- CVE-2026-71429 is a medium-severity vulnerability, classified under Inefficient Algorithmic Complexity. CVSS score: 6.2/10. Published 2026-09-03.
- How severe is CVE-2026-71429?
- Medium severity. CVSS v3 base score is 6.2 out of 10.