# CVE-2026-66010: node-dompurify: DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOM_ELEMENT_HA...

CVE-2026-66010 is fixed in 5 products on 1 platform, first by DEBIAN-CVE-2026-66010, released July 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-66010
- Priority: Routine
- CVSS: n/a (low)
- EPSS: 0.0022
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 24, 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-dompurify Debian 14 | 3.4.12+dfsg-1 | [DEBIAN-CVE-2026-66010](https://patchblox.com/security/data/fix/linux/debian-cve-2026-66010.md) | Jul 25, 2026 |
| Linux | python-jupytext Fedora 43 | 1.19.6-1.fc43 | [FEDORA-2026-3942AB86FD](https://patchblox.com/security/data/fix/linux/fedora-2026-3942ab86fd.md) | Oct 5, 2026 |
| Linux | python-jupytext-doc Fedora 43 | 1.19.6-1.fc43 | [FEDORA-2026-3942AB86FD](https://patchblox.com/security/data/fix/linux/fedora-2026-3942ab86fd.md) | Oct 5, 2026 |
| Linux | python3-jupyterlab-jupytext Fedora 43 | 1.19.6-1.fc43 | [FEDORA-2026-3942AB86FD](https://patchblox.com/security/data/fix/linux/fedora-2026-3942ab86fd.md) | Oct 5, 2026 |
| Linux | python3-jupytext Fedora 43 | 1.19.6-1.fc43 | [FEDORA-2026-3942AB86FD](https://patchblox.com/security/data/fix/linux/fedora-2026-3942ab86fd.md) | Oct 5, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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