diff --git a/support/src/utils/unix.cpp b/support/src/utils/unix.cpp
index be53711e..2f820aca 100644
--- a/support/src/utils/unix.cpp
+++ b/support/src/utils/unix.cpp
@@ -75,6 +75,7 @@ namespace {
 #endif // defined(__APPLE__)
 
 #if !defined(__APPLE__)
+  groups.resize(static_cast<std::size_t>(group_count));
   res = getgrouplist(pass->pw_name, pass->pw_gid, groups.data(), &group_count);
   if (res >= 0) {
     repertory::utils::error::raise_error(