Vulnerability in fast-xml-builder (CVE-2026-44665)
Summary
Vulnerability in fast-xml-builder (CVE-2026-44665). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1.1.7 or later.
Original description
The description as published by the source.
fast-xml-builder builds XML from JSON. Prior to 1.1.7, when an input data has quotes in attribute values but process entities is not enabled, it breaks the attribute value into multiple attributes. This gives the room for an attacker to insert unwanted attributes to the XML/HTML. This vulnerability is fixed in 1.1.7.
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-2026-44665 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 1.1.7 or later.
If unsure, ask your IT team or search "fast-xml-builder CVE-2026-44665" on the vendor's site.
CVE-2026-44665 (fast-xml-builder) — CWE-91 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Patched: 1.1.7 — apply immediately
Workaround: If you're not ignoring attributes then keep processEntities flag true.
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 1.1.7.
Workaround: If you're not ignoring attributes then keep processEntities flag true.
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
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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
If you're not ignoring attributes then keep processEntities flag true.パッチが適用されるまでの応急処置として、If you're not ignoring attributes then keep processEntities flag true. を実施。回避策の副作用 (機能低下) を確認した上で。
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3Apply patch patch
Upgrade fast-xml-builder to 1.1.7ステージング環境で 1.1.7 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。
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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 github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com