Description
KaTeX is a fast, easy-to-use JavaScript library for TeX math rendering on the web. From 0.11.0 until 0.18.2, KaTeX uses ordinary JavaScript property access for the renderer options object, the trust setting, default and processor setting metadata, and namespace lookup and group restoration, allowing inherited properties to be treated as explicitly supplied values. When Object.prototype is already polluted or an attacker controls the options object's prototype, attacker-controlled mathematical expressions can use an inherited trust value to enable trusted rendering and produce links capable of user-interaction cross-site scripting or loading attacker-selected external resources in a consuming application that inserts unsanitized KaTeX output into a page. KaTeX does not itself create the prototype pollution, and rendering an expression alone does not execute script. This issue is fixed in version 0.18.2.
Published: 2026-10-01
Score: 2.1 Low
EPSS: < 1% Very Low
KEV: No
AI Analysis

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Remediation

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Tracking

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Advisories

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History

Fri, 02 Oct 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-79
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N'}

threat_severity

Moderate


Thu, 01 Oct 2026 22:00:00 +0000

Type Values Removed Values Added
First Time appeared Katex
Katex katex
Vendors & Products Katex
Katex katex

Thu, 01 Oct 2026 17:45:00 +0000

Type Values Removed Values Added
Description KaTeX is a fast, easy-to-use JavaScript library for TeX math rendering on the web. From 0.11.0 until 0.18.2, KaTeX uses ordinary JavaScript property access for the renderer options object, the trust setting, default and processor setting metadata, and namespace lookup and group restoration, allowing inherited properties to be treated as explicitly supplied values. When Object.prototype is already polluted or an attacker controls the options object's prototype, attacker-controlled mathematical expressions can use an inherited trust value to enable trusted rendering and produce links capable of user-interaction cross-site scripting or loading attacker-selected external resources in a consuming application that inserts unsanitized KaTeX output into a page. KaTeX does not itself create the prototype pollution, and rendering an expression alone does not execute script. This issue is fixed in version 0.18.2.
Title KaTeX: Existing prototype pollution can bypass trust restrictions
Weaknesses CWE-807
References
Metrics cvssV4_0

{'score': 2.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-01T17:37:47.953Z

Reserved: 2026-10-01T14:20:19.154Z

Link: CVE-2026-103923

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-01T18:17:13.053

Modified: 2026-10-02T18:44:30.817

Link: CVE-2026-103923

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-01T17:37:47Z

Links: CVE-2026-103923 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-02T14:30:24Z

Weaknesses
  • CWE-79

    Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

  • CWE-807

    Reliance on Untrusted Inputs in a Security Decision