CVE-2026-66010

DOMPurify before 3.4.12 Hook Bypass via CUSTOM_ELEMENT_HANDLING

At a glance

Severity: MEDIUM 5.1
EPSS: EPSS 0.21 % · percentile 12 (2026-10-27)
State: PUBLISHED
Published: 2026-07-24
Updated: 2026-09-17
Assigner: VulnCheck
NVD status: Analyzed

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

Version	Score	Vector	Scored by
CVSS 4.0	MEDIUM 5.1	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
CVSS 3.1	MEDIUM 6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	VulnCheck
CVSS 4.0	MEDIUM 5.1	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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD · disclosure@vulncheck.com (Secondary)
CVSS 3.1	MEDIUM 6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	NVD · disclosure@vulncheck.com (Secondary)

Weaknesses (CWE)

CWE-79

Advisories

GHSA-c2j3-45gr-mqc4 — DOMPurify: `CUSTOM_ELEMENT_HANDLING` bypasses `afterSanitizeElements` for allowed custom elements.

European references

ENISA EUVD · EUVD-2026-48582
GCVE · GCVE-0-2026-66010

CERT-FR advisories

CERTFR-2026-AVI-1366 — Multiples vulnérabilités dans les produits Splunk · cert.ssi.gouv.fr
CERTFR-2026-AVI-1291 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-1256 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-1233 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-1165 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-1067 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:cure53:dompurify:*:*:*:*:*:*:*:* < 3.4.12

Affected products

Product	Versions
cure53 · DOMPurify	affected 0 < 3.4.12 ; unaffected 3.4.12

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD