diff --git a/src/api.c b/src/api.c
index adccef3..65a277a 100644
--- a/src/api.c
+++ b/src/api.c
@@ -786,7 +786,7 @@ API int seccomp_export_bpf_mem(const scmp_filter_ctx ctx, void *buf,
                if (BPF_PGM_SIZE(program) > *len)
                        rc = _rc_filter(-ERANGE);
                else
-                       memcpy(buf, program->blks, *len);
+                       memcpy(buf, program->blks, BPF_PGM_SIZE(program));
        }
        *len = BPF_PGM_SIZE(program);
 
