CVE-2026-107299 — msgpack5: Reserved byte can cause unbounded stream buffering
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 …
Published: 2026-10-08 · CVSS: 5.9 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7