Vulnerability in multiparty (CVE-2026-8159)
Summary
Vulnerability in multiparty (CVE-2026-8159). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 4.3.0 or later.
Original description
The description as published by the source.
multiparty@4.2.3 and lower versions are vulnerable to denial of service via regular expression backtracking in the Content-Disposition filename parameter parser. A crafted multipart upload with a long header value can cause regex matching to take seconds, blocking the event loop. Impact: any service accepting multipart uploads via multiparty is affected. Workarounds: limiting upload sizes at the proxy or gateway layer reduces but does not eliminate the attack surface, since a small header of around 8 KB is sufficient to trigger the vulnerable backtracking. Upgrade to multiparty@4.3.0 or higher.
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-2026-8159 has been found in multiparty.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade multiparty to 4.3.0 or later.
If unsure, ask your IT team or search "multiparty CVE-2026-8159" on the vendor's site.
CVE-2026-8159 (multiparty) — CWE-1333 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 4.3.0 — apply immediately
Workaround: None.
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-1333) exists in multiparty.
Check the vendor advisory for the affected versions of multiparty.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 4.3.0.
Workaround: None.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'multiparty' . 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 'multiparty' . | 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
multiparty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
None.パッチが適用されるまでの応急処置として、None. 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 multiparty to 4.3.0ステージング環境で 4.3.0 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
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-8159 node-multiparty
- Ubuntu UBUNTU-CVE-2026-8159 node-multiparty
References
- advisory cna.openjsf.org
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web owasp.org
- web github.com
- web github.com