GHSA-6v7p-g79w-8964High· 7.5▾ TwilightMessagePack for Python: Out-of-bounds read / crash on Unpacker reuse after a caught error
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0 · exploitation 0
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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.
v1.2.1
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.
msgpack <= 1.2.0Upgrade to a patched release:
msgpack 1.2.1Connected by shared product, vendor, weakness, or advisory.
CVE-2026-114613High· 7.5MessagePack: Unbounded memory leak in msgpack C extension on strict_map_key validation failure
CVE-2026-54522LowMessagePack::Buffer#clear Use-After-Free that Enables Cross-Buffer Disclosure
CVE-2026-32284High· 7.5The msgpack decoder fails to properly validate the input buffer length when processing truncated fixext data (format codes 0xd4-0xd8)
CVE-2022-3256High· 7.8Use After Free in GitHub repository vim/vim prior to 9.0.0530.
CVE-2022-3134High· 7.8Use After Free in GitHub repository vim/vim prior to 9.0.0389.
CVE-2022-3297High· 7.8Use After Free in GitHub repository vim/vim prior to 9.0.0579.