Answer in brief
CVE-2026-107300 records a High severity (CVSS 7.5) vulnerability in msgpack5: Many buffered values can exhaust the streaming decoder stack. The current sources do not mark it as known exploited. The current feed maps mcollina/msgpack5 (generic), msgpack5 (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 mcollina/msgpack5 (generic), msgpack5 (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| mcollina/msgpack5generic | <6.1.0 | 6.1.0 |
| msgpack5npm | <6.1.0 | 6.1.0 |
Published upstream
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 8, 2026
msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder recursively invokes itself for each complete MessagePack value remaining in a chunk. A remote peer can send one chunk containing many small valid values, causing recursion proportional to the value count, exhausting the JavaScript call stack, and interrupting the process or stream. This issue is fixed in version 6.1.0.
Quoted source text, attributed separately from HOL analysis.