Modification of assumed-immutable data in msgpack5 - #VU152777
Published: September 29, 2026
Vulnerability identifier: #VU152777
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-471
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to modify caller-provided input data.
The vulnerability exists due to modification of assumed-immutable data in the msgpack5 decoder when decoding a negative signed 64-bit integer. A remote attacker can provide specially crafted MessagePack input to modify caller-provided input data.
Positive integers and other MessagePack value types are not affected.
Affected software
msgpack5
Remediation
Install security update from vendor's website.
msgpack5 - update to 6.1.0