Vulnerability in fast-xml-builder (CVE-2026-44664)
Summary
Vulnerability in fast-xml-builder (CVE-2026-44664). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1.1.6 or later.
Original description
The description as published by the source.
Summary
The fix for https://github.com/advisories/GHSA-gh4j-gqv2-49f6 in fast-xml-parser sanitizes -- sequences in XML comment content using .replace(/--/g, '- -'). This skip the values containing three consecutive dashes (e.g., --->...), allowing an attacker to break out of an XML comment and inject arbitrary XML/HTML content.
Impact
Any application with comment property enabled allow attacker to inject malicious or unwanted code like JS script tag in the XML/HTML output.
Workarounds
Check for the presence of 3 consecutive dashes externally in the property value used for comment tag.
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-2026-44664 has been found in fast-xml-builder.
Risk of unauthorized operations or information disclosure. CVSS score: 6.1/10.
What to do: upgrade fast-xml-builder to 1.1.6 or later.
If unsure, ask your IT team or search "fast-xml-builder CVE-2026-44664" on the vendor's site.
CVE-2026-44664 (fast-xml-builder) — CWE-91 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Patched: 1.1.6 — apply immediately
Workaround: Check for the presence of 3 consecutive dashes externally in the property value used for comment tag.
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-91) exists in fast-xml-builder.
Check the vendor advisory for the affected versions of fast-xml-builder.
Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.
Update to 1.1.6.
Workaround: Check for the presence of 3 consecutive dashes externally in the property value used for comment tag.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'fast-xml-builder' . 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 'fast-xml-builder' . | 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
fast-xml-builderを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
Check for the presence of 3 consecutive dashes externally in the property value used for comment tag.パッチが適用されるまでの応急処置として、Check for the presence of 3 consecutive dashes externally in the property value used for comment tag. を実施。回避策の副作用 (機能低下) を確認した上で。
-
3Apply patch patch
Upgrade fast-xml-builder to 1.1.6ステージング環境で 1.1.6 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。
-
4Post-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
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com