source-map-js allows event-loop denial of service through indexed source-map section offsets
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.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | source-map-js | >= 1.0.0, < 1.2.2 | 1.2.2 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-93749
- https://github.com/7rulnik/source-map-js/issues/76
- https://github.com/7rulnik/source-map-js/pull/79
- https://github.com/7rulnik/source-map-js/commit/cf7658058ceeaa8619d5ae0ec90be6905209d016
- https://github.com/7rulnik/source-map-js
- https://github.com/7rulnik/source-map-js/blob/c1cd8904bb7bd0c7fb5879fcda48134d82a27934/lib/source-node.js#L115-L118
- https://github.com/7rulnik/source-map-js/releases/tag/v1.2.2
- https://www.vulncheck.com/advisories/source-map-js-through-1.2.1-event-loop-denial-of-service
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-1284- Platform
- npm
- Package
source-map-js- Disclosed
- 18.09.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-68fv-2mgg-jv7q - CC BY 4.0
Vulnerability history: source-map-js
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.