diff --git a/reactos/dll/win32/kernel32/client/fiber.c b/reactos/dll/win32/kernel32/client/fiber.c
index 2f7b901d50d..22ece1be4e6 100644
--- a/reactos/dll/win32/kernel32/client/fiber.c
+++ b/reactos/dll/win32/kernel32/client/fiber.c
@@ -195,6 +195,9 @@ CreateFiberEx(SIZE_T dwStackCommitSize,
     Fiber = RtlAllocateHeap(RtlGetProcessHeap(), 0, sizeof(FIBER));
     if (!Fiber)
     {
+        /* Free the activation context stack */
+        RtlFreeActivationContextStack(ActivationContextStack);
+
         /* Fail */
         SetLastError(ERROR_NOT_ENOUGH_MEMORY);
         return NULL;