CVE-2026-107299
msgpack5: Reserved byte can cause unbounded stream buffering
- State
- Published
- Severity
- 5.9 Medium
- Published
- Oct 8, 2026
- Updated
- Oct 9, 2026
- Reserved
- Oct 7, 2026
Description
msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder treats the reserved MessagePack byte 0xc1 as incomplete input instead of invalid input. When 0xc1 begins a stream, subsequent data remains buffered while the decoder waits for bytes that cannot make the value valid, allowing a remote peer to exhaust memory. This issue is fixed in version 6.1.0.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
Weaknesses
- CWE-228 Improper Handling of Syntactically Invalid Structure
Affected Products
| Product | Versions |
|---|---|
msgpack5mcollina |
|
References
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