# CVE-2026-116804: DOMPurify from 3.4.4 before 3.4.17 SAFE_FOR_TEMPLATES Bypass via Shadow Root Content

Status: published. Published: 2026-10-26. Updated: 2026-11-02.

DOMPurify from 3.4.4 before 3.4.17 contains a SAFE_FOR_TEMPLATES bypass that lets attackers preserve template expressions in attached shadow roots when using RETURN_DOM, RETURN_DOM_FRAGMENT, or IN_PLACE modes. Attackers can split expressions across text nodes separated by disallowed elements, which merge after removal and are evaluated by downstream template engines for cross-site scripting.

## Remediation

- fix: dompurify (npm): OSV reports a fixed version 3.4.17. Check the advisory for supported release branches. (source: OSV GHSA-cg2g-xh64-v4q7) — https://github.com/advisories/GHSA-cg2g-xh64-v4q7

## Affected products and versions

- cure53 / DOMPurify (dompurify): ≥ 3.4.4; < 3.4.17 (affected, semver); 3.4.17 (unaffected, semver). Source: CNA: VulnCheck
-  / dompurify (dompurify): ≥ 3.4.4; < 3.4.17 (affected, semver); OSV events: introduced 3.4.4; fixed 3.4.17. Source: OSV GHSA-cg2g-xh64-v4q7

## Severity and prioritization

- CVSS 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; source: CNA: VulnCheck

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: 0.18% as of 2026-11-02; percentile 7.40%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-79

## Exploit evidence

- exploit: https://github.com/cure53/DOMPurify/security/advisories/GHSA-cg2g-xh64-v4q7 (ADP: CISA-ADP)

## References

- https://github.com/cure53/DOMPurify/security/advisories/GHSA-cg2g-xh64-v4q7 (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/dompurify-from-3.4.4-before-3.4.17-safe-for-templates-bypass-via-shadow-root-content (CNA: VulnCheck; third-party-advisory)

- https://github.com/cure53/DOMPurify/security/advisories/GHSA-cg2g-xh64-v4q7 (ADP: CISA-ADP; exploit)

- https://github.com/advisories/GHSA-cg2g-xh64-v4q7 (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-cg2g-xh64-v4q7 (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-116804; retrieved 2026-11-02; source updated 2026-11-02

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-cg2g-xh64-v4q7; retrieved 2026-11-02; source updated 2026-10-27

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-116804; retrieved 2026-11-02; source updated Not reported

Revision: 19be823e005fff83f7135295927ad825480c6c0e63952cc3ed22ede46b60cda7

Canonical: https://y2.dev/cve/CVE-2026-116804

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