GitHub Advisoryadvisory · npm

GHSA-qw35-55vc-rhgj msgpack5: Decoding negative int64 values mutates the input buffer

LOW Published 2026-10-08 Modified 2026-10-08 Official page ↗
Aliases
CVE-2026-107296
Ecosystem
npm
Packages
msgpack5
Severity
Low
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Weaknesses
CWE-471
Reviewed
2026-10-08

Affected packages

• npm msgpack5: < 6.1.0 → fixed in 6.1.0

Description

Impact Decoding a negative signed 64-bit integer modifies the corresponding bytes in the caller-provided input buffer. Applications that retain or reuse encoded input for integrity checks, logging, or subsequent processing may observe silently corrupted data. Positive integers and other MessagePack value types are not affected. Patches The decoder now computes signed 64-bit values without writing to the input buffer. Workarounds Copy untrusted MessagePack input before decoding it, or do not retain or reuse input buffers after decoding.

Related

Alias · CVE (1)

  • CVE-2026-107296 msgpack5 is a msgpack v5 implementation for node.js and the browser. vulnerability

Weakness · CWE (1)

  • CWE-471 Modification of Assumed-Immutable Data (MAID) weakness

References