Update changelog

ChangeLog.md

@@ -1,4 +1,4 @@
-# 12.2.1 - TBD
+# 12.3.0 - TBD
 
 - Added a formatter for `std::exception_ptr` that formats the referenced
   exception (or `none` when null)
@@ -69,6 +69,20 @@
 - Fixed a minor formatting issue in the documentation
   (https://github.com/fmtlib/fmt/pull/4826). Thanks @brooklynwidz.
 
+# 12.2.1 - 2026-11-07
+
+- Fixed a heap buffer overflow on 32-bit targets when the size of a formatting
+  buffer overflows, e.g. `fmt::format(L"{:>{}}", s, 1100000000)`. Such
+  allocations now throw `std::bad_alloc`.
+
+- Fixed an out-of-bounds read when parsing format specifiers of
+  `std::error_code` (https://github.com/fmtlib/fmt/pull/4934).
+  Thanks @IfkumRfnl.
+
+- Fixed a crash when formatting `nullptr` with `FMT_COMPILE` and an exception
+  in `fmt::to_string(nullptr)`; both now format it as `0x0`
+  (https://github.com/fmtlib/fmt/pull/4993). Thanks @INo-xious.
+
 # 12.2.0 - 2026-06-16
 
 - Added a C11 API that brings fast, type-safe formatting to C. The new