CVE-2026-57585

EUVD-2026-40423
MessagePack is the serializer implementation for Python msgpack.org. Prior to 1.2.1, there is an Out-of-bounds read/crash on Unpacker reuse after a caught error, potentially leading to a DoS attack.  If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. This issue has been fixed in version 1.2.1.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.5 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 20.24%
Affected Products (NVD)
VendorProductVersion
msgpackmessagepack
𝑥
< 1.2.1
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
python-msgpack
bookworm
vulnerable
bullseye
vulnerable
forky
1.1.2-4
fixed
sid
1.1.2-4
fixed
trixie
vulnerable
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
python-msgpack
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
questing
ignored
resolute
needs-triage
python-pip
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
questing
ignored
resolute
needs-triage
trusty
needs-triage
python-srsly
jammy
dne
noble
needs-triage
questing
ignored
resolute
needs-triage
Azure Linux logo
Azure Linux Releases
Azure Package
Release
python-msgpack
Azure Linux 3.0
0:1.0.5-3.azl3
fixed
Common Weakness Enumeration
References
https://github.com/msgpack/msgpack-python/commit/2c56ddb5d0025ed481d962c0f5d62d19dec7476d
https://github.com/msgpack/msgpack-python/security/advisories/GHSA-6v7p-g79w-8964