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CVE-2026-49459 medium CVSS 6.1

Vulnerability in dompurify (CVE-2026-49459)

Summary

Vulnerability in dompurify (CVE-2026-49459). Risk of unauthorized operations or information disclosure. Exploitable via _forceRemove. Mitigation: upgrade to 3.4.6 or later.

Original description

The description as published by the source.

IN_PLACE mode preserves attributes of a clobbered root element, allowing XSS via attacker-controlled root DOM

CWE: CWE-79 (XSS — Improper Neutralization of Input During Web Page Generation) via CWE-693 (Protection Mechanism Failure — silent no-op when _forceRemove is called on a parent-less node)

Summary

When DOMPurify.sanitize(root, { IN_PLACE: true }) is called and root is a `` whose own attributes carry an event handler (onmouseover, onfocus, onclick, etc.), a single descendant element with a name= attribute matching any of the property names _isClobbered checks (nodeName, setAttribute, namespaceURI, insertBefore, hasChildNodes, childNodes) is sufficient to bypass attribute sanitization on the root. _forceRemove silently no-ops because the root has no parent; the iterator drives on to _sanitizeAttributes, which early-returns on clobbered nodes — and the event handler attribute is never inspected. The sanitized return is the same root, with the handler live.

This affects current main at 89da34e (the just-landed DOM-clobbering hardening fix at 89da34e addressed _sanitizeAttachedShadowRoots walk traversal, not the main _sanitizeElements / _sanitizeAttributes pipeline against the iterator-root node).

Affected

  • DOMPurify ≤ 3.4.5, including main at 89da34e03ec17868e561f87f3747a9371b61a9e7
  • Any caller that does DOMPurify.sanitize(node, { IN_PLACE: true }) where node is built from untrusted HTML (e.g., par…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

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-2026-49459 has been found in dompurify.
Attackers can target a specific entry point like _forceRemove 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 3.4.6 or later.
If unsure, ask your IT team or search "dompurify CVE-2026-49459" on the vendor's site.

CVE-2026-49459 (dompurify) — CWE-1321 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: _forceRemove / root / onmouseover / onfocus
Patched: 3.4.6 — 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.

❓ What is the problem

A vulnerability (CWE-1321) exists in dompurify. Attackers reach the vulnerable code path via _forceRemove without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of dompurify. Attack surface: _forceRemove / root / onmouseover / onfocus.

🔥 Severity

Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 3.4.6.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

  1. 1
    Identify 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。

  2. 2
    Apply patch patch 
    Upgrade dompurify to 3.4.6

    ステージング環境で 3.4.6 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。

  3. 3
    Post-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

npm dompurify
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.4.6"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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