Cross-Site Scripting (XSS) in dompurify (CVE-2026-65912)
Summary
Cross-site scripting in dompurify (CVE-2026-65912). Risk of unauthorized operations or information disclosure. Exploitable via ADD_ATTR. Mitigation: upgrade to 3.3.2 or later.
Original description
The description as published by the source.
Summary
DOMPurify allows ADD_ATTR to be provided as a predicate function via EXTRA_ELEMENT_HANDLING.attributeCheck. When the predicate returns true, _isValidAttribute short-circuits the attribute check before URI-safe validation runs. An attacker who supplies a predicate that accepts specific attribute/tag combinations can then sanitize input such as `` and have the javascript: URL survive, because URI validation is skipped for that attribute while other checks still pass. The provided PoC accepts href for anchors and then triggers a click inside an iframe, showing that the sanitized payload executes despite the protocol bypass.
Impact
Predicate-based allowlisting bypasses DOMPurify's URI validation, allowing unsafe protocols such as javascript: to reach the DOM and execute whenever the link is activated, resulting in DOM-based XSS.
Credits
Identified by Cantina’s Apex (https://www.cantina.security).
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-65912 has been found in dompurify.
Attackers can target a specific entry point like ADD_ATTR over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.1/10.
What to do: upgrade dompurify to 3.3.2 or later.
If unsure, ask your IT team or search "dompurify CVE-2026-65912" on the vendor's site.
CVE-2026-65912 (dompurify) — CWE-79 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: ADD_ATTR / EXTRA_ELEMENT_HANDLING.attributeCheck / true / _isValidAttribute
Patched: 3.3.2 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Cross-site scripting (XSS) (CWE-79) exists in dompurify. Attackers reach the vulnerable code path via ADD_ATTR without authentication.
Check the vendor advisory for the affected versions of dompurify. Attack surface: ADD_ATTR / EXTRA_ELEMENT_HANDLING.attributeCheck / true / _isValidAttribute.
Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.
Update to 3.3.2.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'dompurify' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'dompurify' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
dompurifyを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade dompurify to 3.3.2ステージング環境で 3.3.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Ubuntu UBUNTU-CVE-2026-65912 node-dompurify
References
- advisory disclosure@vulncheck.com
- advisory disclosure@vulncheck.com
- package github.com
- web github.com
- web github.com