diff --git a/tmux.c b/tmux.c
index d8985159..38ffa05c 100644
--- a/tmux.c
+++ b/tmux.c
@@ -226,7 +226,7 @@ make_label(const char *label, char **cause)
 		xasprintf(cause, "%s is not a directory", base);
 		goto fail;
 	}
-	if (sb.st_uid != uid || (sb.st_mode & S_IRWXO) != 0) {
+	if (sb.st_uid != uid || (sb.st_mode & TMUX_SOCK_PERM) != 0) {
 		xasprintf(cause, "directory %s has unsafe permissions", base);
 		goto fail;
 	}
diff --git a/tmux.h b/tmux.h
index 5e86dac9..3cd882a3 100644
--- a/tmux.h
+++ b/tmux.h
@@ -78,6 +78,9 @@ struct winlink;
 #ifndef TMUX_SOCK
 #define TMUX_SOCK "$TMUX_TMPDIR:" _PATH_TMP
 #endif
+#ifndef TMUX_SOCK_PERM
+#define TMUX_SOCK_PERM (7 /* o+rwx */)
+#endif
 #ifndef TMUX_TERM
 #define TMUX_TERM "screen"
 #endif