Vulnerability in Happy DOM (CVE-2026-34226)
Summary
Vulnerability in Happy DOM (CVE-2026-34226). Confidential information can be exposed externally. Exploitable via window.location.
Original description
The description as published by the source.
Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Versions prior to 20.8.9 may attach cookies from the current page origin (window.location) instead of the request target URL when fetch(..., { credentials: "include" }) is used. This can leak cookies from origin A to destination B. Version 20.8.9 fixes the issue.
Source: NIST National Vulnerability Database 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-2026-34226 has been found in Happy DOM.
Attackers can target a specific entry point like window.location over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Happy DOM CVE-2026-34226" on the vendor's site.
CVE-2026-34226 (Happy DOM) — CWE-201 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: window.location
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.
A vulnerability (CWE-201) exists in Happy DOM. Attackers reach the vulnerable code path via window.location without authentication.
Check the vendor advisory for the affected versions of Happy DOM. Attack surface: window.location.
Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
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. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Happy DOM を使っているサービスとバージョンを洗い出す。
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2Post-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。
References
- advisory github.com
- advisory access.redhat.com
- advisory github.com
- advisory nvd.nist.gov
- patch github.com
- patch github.com
- report bugzilla.redhat.com
- web github.com
- web github.com
- web security.access.redhat.com