diff --git a/diff-lib.c b/diff-lib.c
index 6b14b95962..3cf353946f 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -661,6 +661,7 @@ int do_diff_cache(const struct object_id *tree_oid, struct diff_options *opt)
 
 	repo_init_revisions(opt->repo, &revs, NULL);
 	copy_pathspec(&revs.prune_data, &opt->pathspec);
+	diff_free(&revs.diffopt);
 	revs.diffopt = *opt;
 	revs.diffopt.no_free = 1;
 
diff --git a/t/t7610-mergetool.sh b/t/t7610-mergetool.sh
index 22b3a85b3e..5c5e79e990 100755
--- a/t/t7610-mergetool.sh
+++ b/t/t7610-mergetool.sh
@@ -10,6 +10,7 @@ Testing basic merge tool invocation'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # All the mergetool test work by checking out a temporary branch based