diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6ca4d150..89909886 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,22 @@ All notable changes to EigenScript are documented here.
 
 ## [Unreleased]
 
+## [0.45.1] - 2026-10-07
+
+### Fixed
+
+- **An unsent parameter is null-filled at every call entry, with or without
+  defaults (#1661).** A 2+-parameter callee without defaults, called with
+  fewer arguments than it takes, left the unsent parameters unbound. Once the
+  JIT compiled the callee, reading one read a stale slot of a recycled call
+  env: a heap-use-after-free that aborted release builds in `malloc` (seen in
+  recursion around depth 1000 or more), or a stale non-null value. Even
+  without the JIT, a closure over an unsent parameter resolved the name in an
+  outer scope instead of reading `null`. Direct calls, JIT-to-JIT calls,
+  `dispatch` (both forms) and `task_spawn` now bind every unsent parameter to
+  `null`, as SPEC.md and `docs/llms.txt` already promised. The bug was also
+  present in v0.44.0.
+
 ## [0.45.0] - 2026-10-07
 
 ### Breaking changes
diff --git a/VERSION b/VERSION
index bcce5d06..ff12df2f 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.45.0
+0.45.1
diff --git a/changes/fixed/1661-underarity-param-null-fill.md b/changes/fixed/1661-underarity-param-null-fill.md
deleted file mode 100644
index 3dbf3daa..00000000
--- a/changes/fixed/1661-underarity-param-null-fill.md
+++ /dev/null
@@ -1,11 +0,0 @@
-- **An unsent parameter is null-filled at every call entry, with or without
-  defaults (#1661).** A 2+-parameter callee without defaults, called with
-  fewer arguments than it takes, left the unsent parameters unbound. Once the
-  JIT compiled the callee, reading one read a stale slot of a recycled call
-  env: a heap-use-after-free that aborted release builds in `malloc` (seen in
-  recursion around depth 1000 or more), or a stale non-null value. Even
-  without the JIT, a closure over an unsent parameter resolved the name in an
-  outer scope instead of reading `null`. Direct calls, JIT-to-JIT calls,
-  `dispatch` (both forms) and `task_spawn` now bind every unsent parameter to
-  `null`, as SPEC.md and `docs/llms.txt` already promised. The bug was also
-  present in v0.44.0.