Medium severity6.1NVD Advisory· Published Jul 24, 2026· Updated Aug 6, 2026
CVE-2026-66010
CVE-2026-66010
Description
DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOM_ELEMENT_HANDLING.tagNameCheck, allowing attributes to bypass application security policies. Attackers can preserve sensitive attributes on custom elements that later re-inject them into innerHTML sinks, creating second-order XSS gadgets.
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LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
dompurifynpm | < 3.4.12 | 3.4.12 |
Affected products
3(expand)+ 1 more
- (no CPE)
- (no CPE)
Package: https://rubygems.org/gems/dompurify
Patches
Vulnerability mechanics
References
7- github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4nvdExploitVendor AdvisoryWEB
- github.com/advisories/GHSA-c2j3-45gr-mqc4ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-66010ghsaADVISORY
- www.vulncheck.com/advisories/dompurify-before-hook-bypass-via-custom-element-handlingnvdThird Party AdvisoryWEB
- github.com/cure53/DOMPurify/commit/a9ca1e537422319a557a9a2aa61f003b23b4a197ghsaWEB
- github.com/cure53/DOMPurify/pull/1537ghsaWEB
- github.com/cure53/DOMPurify/releases/tag/3.4.12ghsaWEB
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