From 406360b3a8437f487dfd4732585f276c275649df Mon Sep 17 00:00:00 2001
From: Thomas Kowalski <thom.kowa@gmail.com>
Date: Wed, 29 Apr 2026 11:23:42 +0200
Subject: [PATCH] fix: eliminate memory leak when parsing incorrect nested
 arrays

---
 msgpack/_unpacker.pyx     | 1 +
 msgpack/unpack_template.h | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/msgpack/_unpacker.pyx b/msgpack/_unpacker.pyx
index e25986e..29cdec4 100644
--- a/msgpack/_unpacker.pyx
+++ b/msgpack/_unpacker.pyx
@@ -322,6 +322,7 @@ cdef class Unpacker:
         self.buf = NULL
 
     def __dealloc__(self):
+        unpack_clear(&self.ctx)
         PyMem_Free(self.buf)
         self.buf = NULL
 
diff --git a/msgpack/unpack_template.h b/msgpack/unpack_template.h
index cce29e7..4230661 100644
--- a/msgpack/unpack_template.h
+++ b/msgpack/unpack_template.h
@@ -72,6 +72,14 @@ static inline PyObject* unpack_data(unpack_context* ctx)
 
 static inline void unpack_clear(unpack_context *ctx)
 {
+    unsigned int i;
+    for (i = 1; i < ctx->top; i++) {
+        Py_CLEAR(ctx->stack[i].obj);
+        /* map_key holds a live reference only while waiting for the value */
+        if (ctx->stack[i].ct == CT_MAP_VALUE) {
+            Py_CLEAR(ctx->stack[i].map_key);
+        }
+    }
     Py_CLEAR(ctx->stack[0].obj);
 }