diff --git a/ui-atom.c b/ui-atom.c
index 41838d3..3866823 100644
--- a/ui-atom.c
+++ b/ui-atom.c
@@ -63,7 +63,7 @@ static void add_entry(struct commit *commit, const char *host)
 		html_attr(pageurl);
 		if (ctx.cfg.virtual_root)
 			delim = '?';
-		htmlf("%cid=%s", delim, hex);
+		html_attrf("%cid=%s", delim, hex);
 		html("'/>\n");
 		free(pageurl);
 	}