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.
GHSA-68fv-2mgg-jv7q
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:GHSA-68fv-2mgg-jv7q
source-map-js
Source reference: /affected/0/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 1.2.2
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "1.0.0"
},
{
"fixed": "1.2.2"
}
]
}
],
"package": {
"name": "source-map-js",
"purl": "pkg:npm/source-map-js",
"ecosystem": "npm"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-68fv-2mgg-jv7q/GHSA-68fv-2mgg-jv7q.json"
}
}
]- Related CVEs
- CVE-2026-93749
Source reference:
/aliases
Publisher severity
high
Source reference: /database_specific/severity
- Event
- #85941 · Revision 1
- Added to Heist Feed
- Publisher date