CVE-2026-107297
msgpack5: Quadratic parsing in the streaming decoder
CVSS Score
5.9
EPSS Score
0.0%
EPSS Percentile
0th
msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder reparses an incomplete array or map from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack container across many small chunks, causing completed elements to be decoded repeatedly, producing quadratic CPU use and blocking the event loop. This issue is fixed in version 6.1.0.
| CWE | CWE-407 |
| Vendor | mcollina |
| Product | msgpack5 |
| Published | Oct 8, 2026 |
| Last Updated | Oct 8, 2026 |
Stay Ahead of the Next One
Get instant alerts for mcollina msgpack5
Be the first to know when new medium vulnerabilities affecting mcollina msgpack5 are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
mcollina / msgpack5
< 6.1.0