CVE-2026-116538

EUVD-2026-109908
HtmlSanitizer before 9.2.1039 and 10.0 prereleases before 10.0.1037-beta contains a cross-site scripting vulnerability because SanitizeDom(string) never sanitizes attributes on the html and body wrapper elements. Attackers can supply input with a second body or html tag carrying event handlers like onload, executing script when applications render serialized document or body outer HTML.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
4.7 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: 21.16%
Common Weakness Enumeration
References
https://github.com/mganss/HtmlSanitizer
https://github.com/mganss/HtmlSanitizer/blob/v9.2.995/src/HtmlSanitizer/HtmlSanitizer.cs#L456-L465
https://github.com/mganss/HtmlSanitizer/blob/v9.2.995/src/HtmlSanitizer/HtmlSanitizer.cs#L555-L583
https://github.com/mganss/HtmlSanitizer/commit/96afbc818e64de7571ea17954a05d523e819c56f
https://github.com/mganss/HtmlSanitizer/commit/ab626e7a4f2893f7e9ec0a72779ae19c5ec439a7
https://github.com/mganss/HtmlSanitizer/releases/tag/v10.0.1037-beta
https://github.com/mganss/HtmlSanitizer/releases/tag/v9.2.1039
https://joshua.hu/htmlsanitizer-sanitizedom-body-html-attribute-bypass
https://www.vulncheck.com/advisories/htmlsanitizer-before-9.2.1039-xss-via-sanitizedom-body-and-html-attributes