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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.0035.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
7rulnik source-map-js unaffected
Version Status Constraints
0 affected ≤ 1.2.1

No data.

No data.

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Project Subscriptions

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/7rulnik/source-map-js cve-icon cve-icon
https://github.com/7rulnik/source-map-js/blob/c1cd8904bb7bd0c7fb5879fcda48134d82a27934/lib/source-node.js#L115-L118 cve-icon cve-icon
https://github.com/7rulnik/source-map-js/issues/76 cve-icon cve-icon
https://www.vulncheck.com/advisories/source-map-js-through-1.2.1-event-loop-denial-of-service cve-icon cve-icon
History

Fri, 18 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
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.
Title source-map-js through 1.2.1 Event Loop Denial of Service
Weaknesses CWE-1284
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-18T17:51:34.972Z

Reserved: 2026-09-18T16:30:17.433Z

Link: CVE-2026-93749

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-18T18:18:33.480

Modified: 2026-09-18T18:18:33.480

Link: CVE-2026-93749

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-19T16:30:17Z

Weaknesses