diff --git a/internal/gitaly/service/diff/commit_diff_test.go b/internal/gitaly/service/diff/commit_diff_test.go
index fc7cd89f7bd3b953cd545c102890cebd63fd95d6..40b21f7ea3ab2f59b0967a7c22d904d0d4a11d35 100644
--- a/internal/gitaly/service/diff/commit_diff_test.go
+++ b/internal/gitaly/service/diff/commit_diff_test.go
@@ -2,6 +2,7 @@ package diff
 
 import (
 	"errors"
+	"fmt"
 	"io"
 	"strings"
 	"testing"
@@ -1134,7 +1135,11 @@ func TestCommitDiff_nonexistentCommit(t *testing.T) {
 	})
 	require.NoError(t, err)
 
-	testhelper.RequireGrpcError(t, structerr.NewFailedPrecondition("eachDiff: exit status 128"), drainCommitDiffResponse(stream))
+	testhelper.RequireGrpcError(t, testhelper.WithInterceptedMetadata(
+		structerr.NewFailedPrecondition("eachDiff: exit status 128"),
+		"stderr", fmt.Sprintf("fatal: bad object %s\n", nonExistentCommitID.String()),
+	),
+		drainCommitDiffResponse(stream))
 }
 
 func getDiffsFromCommitDiffClient(t *testing.T, client gitalypb.DiffService_CommitDiffClient) []*diff.Diff {
diff --git a/internal/gitaly/service/diff/utils.go b/internal/gitaly/service/diff/utils.go
index 5b53cd63e6a5629e253ac5ab6c82ce7b9d7fcf1f..81558182deddfaa637152785ec9a28f2cb416b15 100644
--- a/internal/gitaly/service/diff/utils.go
+++ b/internal/gitaly/service/diff/utils.go
@@ -1,6 +1,7 @@
 package diff
 
 import (
+	"bytes"
 	"context"
 	"errors"
 
@@ -36,7 +37,8 @@ func validateRequest(ctx context.Context, locator storage.Locator, in requestWit
 func (s *server) eachDiff(ctx context.Context, repo *localrepo.Repo, objectHash git.ObjectHash, subCmd gitcmd.Command, limits diff.Limits, callback func(*diff.Diff) error) error {
 	diffConfig := gitcmd.ConfigPair{Key: "diff.noprefix", Value: "false"}
 
-	cmd, err := repo.Exec(ctx, subCmd, gitcmd.WithConfig(diffConfig), gitcmd.WithSetupStdout())
+	var cmdStderr bytes.Buffer
+	cmd, err := repo.Exec(ctx, subCmd, gitcmd.WithConfig(diffConfig), gitcmd.WithSetupStdout(), gitcmd.WithStderr(&cmdStderr))
 	if err != nil {
 		return structerr.NewInternal("cmd: %w", err)
 	}
@@ -54,7 +56,9 @@ func (s *server) eachDiff(ctx context.Context, repo *localrepo.Repo, objectHash
 	}
 
 	if err := cmd.Wait(); err != nil {
-		return structerr.NewFailedPrecondition("%w", err)
+		return structerr.NewFailedPrecondition("%w", err).WithMetadataItems(
+			structerr.MetadataItem{Key: "stderr", Value: cmdStderr.String()},
+		)
 	}
 
 	return nil