Vulnerability · Published Sep 18, 2026 · Assigned by VulnCheck
CVE-2026-93749source-map-js through 1.2.1 Event Loop Denial of Service
High 7.5
In plain English
A high-severity security flaw in source-map-js from 7rulnik. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | node-postcss | no fix listed | DEBIAN-CVE-2026-93749 |
| Debian:13 | node-postcss | no fix listed | DEBIAN-CVE-2026-93749 |
| Debian:14 | node-postcss | 8.5.31+~cs10.2.26-1 | DEBIAN-CVE-2026-93749 |
| Ubuntu:22.04:LTS | node-postcss | no fix listed | UBUNTU-CVE-2026-93749 |
| Ubuntu:24.04:LTS | node-postcss | no fix listed | UBUNTU-CVE-2026-93749 |
| Ubuntu:26.04:LTS | node-postcss | no fix listed | UBUNTU-CVE-2026-93749 |
| Ubuntu:26.10 | node-postcss | no fix listed | UBUNTU-CVE-2026-93749 |
| npm | source-map-js | 1.2.2 | GHSA-68fv-2mgg-jv7q |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| 7rulnik | source-map-js | 0 – through 1.2.1 |
Weakness: CWE-1284 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- GitHub Issue #76 issue-tracking
- https://github.com/7rulnik/source-map-js product
- line-padding loop driven by the unvalidated section offset line technical-description
- VulnCheck Advisory: source-map-js through 1.2.1 Event Loop Denial of Service third-party-advisory