Missing Release of Memory after Effective Lifetime Affecting msgpack package, versions [1.2.2,1.2.3)
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- published22 Oct 2026
- disclosed22 Oct 2026
- creditUnknown
Introduced: 22 Oct 2026
NewCVE-2026-114613 (opens in a new tab)How to fix?
Upgrade msgpack to version 1.2.3 or higher.
Overview
msgpack is an efficient binary serialization format.
Affected versions of this package are vulnerable to Missing Release of Memory after Effective Lifetime via a use-after-free condition in the unpackb function and the Unpacker streaming class in msgpack/_unpacker.pyx. The fix reveals that unpack_data() returned a borrowed reference to a result object stored inside the unpack context, while unpack_clear() was called after the reference was already used - or, in the unpackb path, only outside the finally block, meaning an exception raised by ExtraData could cause the context to be cleared while the result object was still live. An attacker supplying a malformed or oversized msgpack payload can trigger this condition, causing a crash.