highCVSS 7.5Vulnerability

GHSA-6v7p-g79w-8964

### Impact If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. If the Unpacker is used repeatedly to unpack untrusted input from external sources, it may be vulnerable to a DoS attack. ### Patches v1.2.1 ### Workarounds Users should create a new Unpacker instead of reusing the same Unpacker after an error occurs. Applying the above patch can prevent SEGV, but reusing the Streaming Unpacker after it has encountered an error will not yield correct data. If an error occurs during Streaming Unpacking, the Stream and Streaming Unpacker should be discarded. Therefore, this is not just a workaround but the correct solution. The above patch only prevents crashes from incorrect usage.

Properties

ghsa_id
GHSA-6v7p-g79w-8964
summary
MessagePack for Python: Out-of-bounds read / crash on Unpacker reuse after a caught error
severity
high
cvss_score
7.5
cve_id
GHSA-6v7p-g79w-8964
cvss_vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
is_ghsa_only
true
ghsa_published
2026-06-19T21:42:55Z
source_url
https://github.com/advisories/GHSA-6v7p-g79w-8964
ghsa_updated
2026-06-19T21:42:55Z

Related Entities (4)

REPORTED_BY (1)

[Source]GitHub Advisory Database

VULNERABLE_TO (1)

[Software]pip/msgpack

AFFECTS (1)

[Software]pip/msgpack

HAS_WEAKNESS (1)

[Weakness]Use After Free

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GHSA-6v7p-g79w-8964 (CVSS 7.5) — Ninja Signal Threat Intelligence | Ninja Signal