diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectReader.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectReader.java
index ae0cf42b1..69b2b5104 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectReader.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectReader.java
@@ -512,9 +512,12 @@ public ObjectReachabilityChecker createObjectReachabilityChecker(
 	 *         (default is
 	 *         {@value org.eclipse.jgit.lib.CoreConfig#DEFAULT_COMMIT_GRAPH_ENABLE}).
 	 *
+	 * @throws IOException
+	 *             if it cannot open any of the underlying commit graph.
+	 *
 	 * @since 6.5
 	 */
-	public Optional<CommitGraph> getCommitGraph() {
+	public Optional<CommitGraph> getCommitGraph() throws IOException {
 		return Optional.empty();
 	}
 
@@ -661,7 +664,7 @@ public BitmapIndex getBitmapIndex() throws IOException {
 		}
 
 		@Override
-		public Optional<CommitGraph> getCommitGraph() {
+		public Optional<CommitGraph> getCommitGraph() throws IOException{
 			return delegate().getCommitGraph();
 		}
 
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevWalk.java b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevWalk.java
index a66e7c86b..9da710556 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevWalk.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevWalk.java
@@ -1173,8 +1173,13 @@ byte[] getCachedBytes(RevObject obj, ObjectLoader ldr)
 	@NonNull
 	CommitGraph commitGraph() {
 		if (commitGraph == null) {
-			commitGraph = reader != null ? reader.getCommitGraph().orElse(EMPTY)
-					: EMPTY;
+			try {
+				commitGraph = reader != null
+						? reader.getCommitGraph().orElse(EMPTY)
+						: EMPTY;
+			} catch (IOException e) {
+				commitGraph = EMPTY;
+			}
 		}
 		return commitGraph;
 	}