diff --git a/leak_detector/README.md b/leak_detector/README.md
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+# Leak detector
+
+Matches all calls to `malloc` and `free` and shows any unmatched `malloc` call
+with a Bbcount to jump to.
+
+## Usage
+```
+ugo start
+mleak
+```
+
+Before using the script it must be loaded in to the debugger:
+```
+source PATHTOADDONS/leak_detector/leak_detector.py
+```
diff --git a/leak_detector/leak_detector.py b/leak_detector/leak_detector.py
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+"""
+Find memory leaks when malloc and free are used.
+Starting from the current position it matches all calls to malloc
+with calls to free with the same pointer and
+keeps track of the calls that have no corresponding call to free.
+It is recommended to go to the start of time and then use the command.
+It prints a full list of unmatched calls at the end.
+    Usage: mleak
+
+Contibutors:  Emiliano Testa
+Copyright (C) 2022 Undo Ltd
+"""
+
+import copy
+import gdb
+
+from undodb.debugger_extensions import (
+    udb,
+)
+
+
+ALLOC_FN = "malloc"
+FREE_FN = "free"
+all_allocs = []
+
+
+class MemAlloc:
+    def __init__(self, addr, size, bbcount):
+        self.addr = addr
+        self.size = size
+        self.bbcount = bbcount
+
+
+def handle_alloc_fn():
+    frame = gdb.selected_frame()
+    size = frame.read_register("rdi")
+    bbcount = udb.time.get().bbcount
+    gdb.execute("finish")
+    frame = gdb.selected_frame()
+    addr = frame.read_register("rax")
+    all_allocs.append(MemAlloc(addr, size, bbcount))
+
+
+def handle_free_fn():
+    frame = gdb.selected_frame()
+    addr = frame.read_register("rdi")
+    for alloc in copy.copy(all_allocs):
+        if alloc.addr == addr:
+            all_allocs.remove(alloc)
+
+
+def handle_bp_event(event):
+    if hasattr(event, "breakpoints"):
+        for bp in event.breakpoints:
+            if bp.location == ALLOC_FN:
+                handle_alloc_fn()
+            elif bp.location == FREE_FN:
+                handle_free_fn()
+
+
+class LeakDetect(gdb.Command):
+    def __init__(self):
+        super().__init__("mleaks", gdb.COMMAND_USER)
+
+    @staticmethod
+    def invoke(arg, from_tty):
+        gdb.Breakpoint(ALLOC_FN)
+        gdb.Breakpoint(FREE_FN)
+        gdb.events.stop.connect(handle_bp_event)
+        end_of_time = udb.get_event_log_extent().max_bbcount
+        gdb.execute("continue")
+        while udb.time.get().bbcount < end_of_time:
+            gdb.execute("continue")
+        print("Calls to allocator fn that don't have a corresponding free")
+        for alloc in all_allocs:
+            print(f"{hex(alloc.addr)} - {hex(alloc.size)} - {alloc.bbcount}")
+
+
+LeakDetect()