Disclosure summary
source-map-js through 1.2.1 fails to validate the per-section offset line value in indexed source maps, allowing attackers to specify arbitrary numeric values. Attackers can supply extremely large offset line values that cause synchronous event loop blocking for extended periods, preventing the service from handling other requests.
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
GitHub Reviewed Security Advisories · GHSA-68fv-2mgg-jv7q
Open original source · Updated Oct 05, 2026
source-map-js allows event-loop denial of service through indexed source-map section offsets
Source severity: HIGH / 8.7
| Ecosystem | Package | Affected range | First patched |
|---|---|---|---|
| npm | source-map-js | >= 1.0.0, < 1.2.2 | 1.2.2 |
Original records & references
- NIST NVD record
- CVE Program record
- github.com — Reviewed advisory
PUBLISHED 2026-09-18T14:31:44-04:00
MODIFIED 2026-10-05T19:31:22-04:00
INGESTED 2026-10-06T11:45:33-04:00