multiparty vulnerable to Denial of Service via unbounded part-header accumulation (CVE-2026-87908) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-87908

multiparty vulnerable to Denial of Service via unbounded part-header accumulation

Answer in brief

CVE-2026-87908 records a Unknown severity vulnerability in multiparty vulnerable to Denial of Service via unbounded part-header accumulation. The current sources do not mark it as known exploited. The current feed maps multiparty/multiparty (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Sep 11, 2026Source checked Sep 11, 2026First seen by HOL Sep 11, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps multiparty/multiparty (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
multiparty/multipartygeneric	>=2.1.0 <4.3.1	4.3.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for multiparty/multiparty.
Review the reported fix. Update multiparty/multiparty to 4.3.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source description

multiparty is a Node.js library for parsing multipart/form-data request bodies. In versions from 2.1.0 up to but not including 4.3.1, the parser does not bound the amount of memory used while accumulating the headers of a single multipart part. An unauthenticated attacker can send a single request whose part carries a very large volume of header bytes, forcing the parser to buffer all of them and exhausting the process memory, which crashes the server. This is a denial of service with no confidentiality or integrity impact. The issue is fixed in multiparty 4.3.1, which caps the size of the accumulated part headers. Users should upgrade to multiparty 4.3.1 or later.

Quoted source text, attributed separately from HOL analysis.