CVE-2020-26870: CURE53 Dompurify

Medium severity, CVSS 6.1. EPSS: 4.9% chance of exploitation in the next 30 days.

Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.

Affected products

• CURE53 Dompurify: before 2.0.17 (fixed in 2.0.17)
• Debian Debian Linux: version 9.0 only
• Microsoft Visual Studio 2017: version 15.9 only
• Microsoft Visual Studio 2019: version 16.0 only; version 16.4 only; version 16.7 only; version 16.8 only
• Oracle Application Express: before 21.1.0.00.01 (fixed in 21.1.0.00.01)

Published 2020-10-07. Last modified 2026-06-17.