---
cve: "CVE-2026-66010"
severity: "MEDIUM"
cvss: 5.1
epss: "0.2%"
vendor: "cure53"
kev: false
exploited: false
published: "2026-07-24 12:07:57"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T06:06:37+02:00"
---

# CVE-2026-66010

> 5.1 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
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
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |

## Patch verfügbar (OSV)

- a9ca1e537422319a557a9a2aa61f003b23b4a197 (Commit)

## Referenzen

- <https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4>
- <https://www.vulncheck.com/advisories/dompurify-before-hook-bypass-via-custom-element-handling>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-66010) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_