Answer in brief
CVE-2026-77078 records a High severity (CVSS 7.5) vulnerability in multer vulnerable to Denial of Service via crafted multipart field names. The current sources do not mark it as known exploited. The current feed maps multer/multer (generic), multer (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. 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.
The current feed maps multer/multer (generic), multer (npm). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:expressjs:multer:*:*:*:*:*:node.js:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| multer/multergeneric | >=0 <2.3.0 | 2.3.0 |
| multernpm | <2.3.0 | 2.3.0 |
Published upstream
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 28, 2026
multer is a middleware for handling multipart/form-data in Node.js. A small multipart request containing two specially crafted text field names can cause an uncaught RangeError (Invalid array length) that terminates the Node.js process. The first field uses a very large numeric array index to allocate a maximum-length sparse array, and a second field then pushes past that length, which throws inside the append-field dependency and is not caught by multer. All versions before 2.3.0 are affected, and the issue is a remotely triggerable denial of service. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate.
Quoted source text, attributed separately from HOL analysis.