diff --git a/repos/os/include/framebuffer_session/connection.h b/repos/os/include/framebuffer_session/connection.h
index fd86684010..38202b5351 100644
--- a/repos/os/include/framebuffer_session/connection.h
+++ b/repos/os/include/framebuffer_session/connection.h
@@ -41,6 +41,7 @@ class Framebuffer::Connection : public Genode::Connection<Session>,
 
 			enum { ARGBUF_SIZE = 128 };
 			char argbuf[ARGBUF_SIZE];
+			argbuf[0] = 0;
 
 			/* donate ram quota for storing server-side meta data */
 			Arg_string::set_arg(argbuf, sizeof(argbuf), "ram_quota", RAM_QUOTA);