Mammoth.js 1.3.0 before 1.12.3 contains a regular expression denial of service vulnerability in the style map tokeniser in lib/styles/parser/tokeniser.js due to overlapping regex alternatives. Attackers can supply a crafted .docx with an unterminated quoted string of repeated backslash escapes in mammoth/style-map to block the Node.js event loop.

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.

No EPSS score available.

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
mwilliamson mammoth.js unaffected
Version Status Constraints
1.3.0 affected < 1.12.3

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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/mwilliamson/mammoth.js cve-icon
https://github.com/mwilliamson/mammoth.js/blob/1.12.2/lib/styles/parser/tokeniser.js#L6-L30 cve-icon
https://github.com/mwilliamson/mammoth.js/commit/dc49225425c2c07de0a6dc3529f2386c82a032b4 cve-icon
https://github.com/mwilliamson/mammoth.js/issues/487 cve-icon
https://www.vulncheck.com/advisories/mammoth-js-1.3.0-before-1.12.3-redos-via-style-map-tokeniser cve-icon
History

Sun, 04 Oct 2026 17:30:00 +0000

Type Values Removed Values Added
Description Mammoth.js 1.3.0 before 1.12.3 contains a regular expression denial of service vulnerability in the style map tokeniser in lib/styles/parser/tokeniser.js due to overlapping regex alternatives. Attackers can supply a crafted .docx with an unterminated quoted string of repeated backslash escapes in mammoth/style-map to block the Node.js event loop.
Title Mammoth.js 1.3.0 before 1.12.3 ReDoS via Style Map Tokeniser
Weaknesses CWE-1333
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: 2026-10-04T17:09:54.186Z

Reserved: 2026-10-04T13:04:00.479Z

Link: CVE-2026-105219

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses