diff --git a/CHANGELOG.md b/CHANGELOG.md
index 323543c9..0e7d2590 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,22 @@
+# 1.2.4
+
+Release Date: 2026-10-27
+
+- Limit container preallocation to 10000 items to prevent excessive memory
+  allocation from deeply nested, large array or map headers. Larger containers
+  grow as their contents are decoded; `max_array_len` and `max_map_len` still
+  limit their total size.
+  See [GHSA-j8c6-9vc5-hj6x](https://github.com/msgpack/msgpack-python/security/advisories/GHSA-j8c6-9vc5-hj6x).
+- Pass a list of pairs to `object_pairs_hook` in the pure Python unpacker,
+  ensuring that the entire map is consumed even if the hook does not iterate
+  over its argument. #744
+- Leave the next object unread when `read_array_header()` or `read_map_header()`
+  raises `ValueError` for a mismatched type in the pure Python unpacker. #748
+- Return `bytes` from `Unpacker.read_bytes()` in the pure Python implementation,
+  matching the C extension. #747
+- Update GitHub Actions dependencies, including cibuildwheel to 4.3.1. #749
+
+
 # 1.2.3
 
 Release Date: 2026-09-29
diff --git a/SECURITY.md b/SECURITY.md
index 75f0c541..3737da07 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -1,5 +1,5 @@
-## Security contact information
+## Reporting a Vulnerability
 
-To report a security vulnerability, please use the
-[Tidelift security contact](https://tidelift.com/security).
-Tidelift will coordinate the fix and disclosure.
\ No newline at end of file
+If you discover a security vulnerability, please report it privately using [GitHub's vulnerability reporting feature](https://github.com/msgpack/msgpack-python/security/advisories/new).
+
+Please do not disclose security vulnerabilities through public GitHub issues.
diff --git a/msgpack/__init__.py b/msgpack/__init__.py
index 0947863f..1bbdbbaf 100644
--- 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, 3)
-__version__ = "1.2.3"
+version = (1, 2, 4)
+__version__ = "1.2.4"
 
 
 if os.environ.get("MSGPACK_PUREPYTHON"):