diff --git a/lib/tpm-common.c b/lib/tpm-common.c
index 4277846fdd..82ffdc5341 100644
--- a/lib/tpm-common.c
+++ b/lib/tpm-common.c
@@ -176,6 +176,11 @@ u32 tpm_sendrecv_command(struct udevice *dev, const void *command,
 	}
 
 	size = tpm_command_size(command);
+
+	/* sanity check, which also helps coverity */
+	if (size > COMMAND_BUFFER_SIZE)
+		return log_msg_ret("size", -E2BIG);
+
 	log_debug("TPM request [size:%d]: ", size);
 	for (i = 0; i < size; i++)
 		log_debug("%02x ", ((u8 *)command)[i]);