# CVE-2026-41240

> Vulnerability · severity: **MEDIUM** (CVSS 6.1).

## Description

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions prior to 3.4.0 have an inconsistency between FORBID_TAGS and FORBID_ATTR handling when function-based ADD_TAGS is used. Commit c361baa added an early exit for FORBID_ATTR at line 1214. The same fix was not applied to FORBID_TAGS. At line 1118-1123, when EXTRA_ELEMENT_HANDLING.tagCheck returns true, the short-circuit evaluation skips the FORBID_TAGS check entirely. This allows forbidden elements to survive sanitization with their attributes intact. Version 3.4.0 patches the issue.

## Key facts

- **CVE ID:** CVE-2026-41240
- **Published:** 2026-04-23
- **CVSS severity:** MEDIUM
- **CVSS base score:** 6.1
- **CWE codes:** CWE-79, CWE-183

## Affected products

- `cure53:dompurify`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41240

## Citation

> AI Analytics. CVE-2026-41240. Retrieved 2026-07-07 from https://api.ai-analytics.org/cve/CVE-2026-41240. Derived from NIST NVD. Licensed CC0.

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