diff --git a/src/LibPaths.cc b/src/LibPaths.cc
index 21c9606..f56d1f7 100644
--- a/src/LibPaths.cc
+++ b/src/LibPaths.cc
@@ -79,7 +79,7 @@ void LibPaths::compute_bin_path(const char * argv0)
                     char * semi = strchr(next, ':');
                     if (semi)   *semi = 0;
                     DynArray(char, filename, plen + alen + 10);
-                    snprintf(&filename[0], sizeof(plen + alen + 8), "%s/%s",
+                    snprintf(&filename[0], sizeof(filename), "%s/%s",
                              next, argv0);
 
                     if (access(&filename[0], X_OK) == 0)