source-map-js through 1.2.1 Event Loop Denial of Service (CVE-2026-93749) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-93749

source-map-js through 1.2.1 Event Loop Denial of Service

Answer in brief

CVE-2026-93749 records a Unknown severity vulnerability in source-map-js through 1.2.1 Event Loop Denial of Service. The current sources do not mark it as known exploited. The current feed maps 7rulnik/source-map-js (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 18, 2026Updated Sep 18, 2026Source checked Sep 18, 2026First seen by HOL Sep 18, 2026Material review Sep 18, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps 7rulnik/source-map-js (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
7rulnik/source-map-jsgeneric	0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for 7rulnik/source-map-js.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 18, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 18, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 18, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.