CVE-2026-66010
DOMPurify before 3.4.12 Hook Bypass via CUSTOM_ELEMENT_HANDLING
- State
- Published
- Severity
- 5.1 Medium
- Published
- Jul 24, 2026
- Updated
- Sep 17, 2026
- Reserved
- Jul 23, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.1 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N | VulnCheck |
| 3.1 | 6.1 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N | VulnCheck |
Weaknesses
- CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Products
| Product | Versions |
|---|---|
DOMPurifycure53 |
|
References
- GitHub Security Advisory (GHSA-c2j3-45gr-mqc4)vendor-advisory
- VulnCheck Advisory: DOMPurify before 3.4.12 Hook Bypass via CUSTOM_ELEMENT_HANDLINGthird-party-advisory
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