msgpack · methane · Jun 18, 2026 · Jun 18, 2026 · Jun 18, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,12 @@
+# 1.2.1
+
+Release Date: 2026-06-19
+
+Fix a segfault when calling `Unpacker.unpack()` or `Unpacker.skip()` after an unpacking failure.
+But note that reusing the same `Unpacker` instance after an unpacking failure is not supported.
+Please create a new `Unpacker` instance instead. GHSA-6v7p-g79w-8964
+
+
 # 1.2.0

 Release Date: 2026-06-11

diff --git a/README.md b/README.md
@@ -72,6 +72,10 @@ for unpacked in unpacker:
    print(unpacked)
 ```

+> [!IMPORTANT]
+> If `Unpacker.unpack()` stops with an exception other than `OutOfData`, that `Unpacker` cannot be reused.
+> Create a new `Unpacker` when reading another stream.
+

 ### Packing/unpacking of custom data types

@@ -220,7 +224,7 @@ When upgrading from msgpack-0.4 or earlier, do `pip uninstall msgpack-python` be

  * The extension module no longer supports Python 2.
    The pure Python implementation (`msgpack.fallback`) is used for Python 2.
-  
+
  * msgpack 1.0.6 drops official support of Python 2.7, as pip and
    GitHub Action "setup-python" no longer supports Python 2.7.


diff --git a/msgpack/__init__.py b/msgpack/__init__.py
@@ -4,8 +4,8 @@
 from .exceptions import *  # noqa: F403
 from .ext import ExtType, Timestamp

-version = (1, 2, 0)
-__version__ = "1.2.0"
+version = (1, 2, 1)
+__version__ = "1.2.1"


 if os.environ.get("MSGPACK_PUREPYTHON"):