---
id: CVE-2026-93749
title: >-
  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
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
  synchronou…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-1284
vendor: 7rulnik
product: source-map-js
affected:
  - source-map-js <= 1.2.1
published: '2026-09-18'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:18:33.480'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93749'
references:
  - url: 'https://github.com/7rulnik/source-map-js'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/7rulnik/source-map-js/blob/c1cd8904bb7bd0c7fb5879fcda48134d82a27934/lib/source-node.js#L115-L118
    label: disclosure@vulncheck.com
  - url: 'https://github.com/7rulnik/source-map-js/issues/76'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/source-map-js-through-1.2.1-event-loop-denial-of-service
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-18T18:47:53.268Z'
epss: 0.0035
epssPercentile: 0.28636
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.