diff --git a/core/src/mast/mod.rs b/core/src/mast/mod.rs
index 4a3561172b..fffc1956fb 100644
--- a/core/src/mast/mod.rs
+++ b/core/src/mast/mod.rs
@@ -255,7 +255,7 @@ impl fmt::Display for MastNodeId {
 // ================================================================================================
 
 /// Represents the types of errors that can occur when dealing with MAST forest.
-#[derive(Debug, thiserror::Error)]
+#[derive(Debug, thiserror::Error, PartialEq)]
 pub enum MastForestError {
     #[error(
         "invalid node count: MAST forest exceeds the maximum of {} nodes",
diff --git a/core/src/mast/serialization/tests.rs b/core/src/mast/serialization/tests.rs
index 1d3e2d90be..f2856848f5 100644
--- a/core/src/mast/serialization/tests.rs
+++ b/core/src/mast/serialization/tests.rs
@@ -3,7 +3,8 @@ use miden_crypto::{hash::rpo::RpoDigest, Felt};
 
 use super::*;
 use crate::{
-    operations::Operation, AdviceInjector, AssemblyOp, DebugOptions, Decorator, SignatureKind,
+    mast::MastForestError, operations::Operation, AdviceInjector, AssemblyOp, DebugOptions,
+    Decorator, SignatureKind,
 };
 
 /// If this test fails to compile, it means that `Operation` or `Decorator` was changed. Make sure
@@ -321,3 +322,40 @@ fn serialize_deserialize_all_nodes() {
 
     assert_eq!(mast_forest, deserialized_mast_forest);
 }
+
+#[test]
+fn mast_forest_invalid_node_id() {
+    // Hydrate a forest smaller than the second
+    let mut forest = MastForest::new();
+    let first = forest.add_block(vec![Operation::U32div], None).unwrap();
+    let second = forest.add_block(vec![Operation::U32div], None).unwrap();
+
+    // Hydrate a forest larger than the first to get an overflow MastNodeId
+    let mut overflow_forest = MastForest::new();
+    let overflow = (0..=3)
+        .map(|_| overflow_forest.add_block(vec![Operation::U32div], None).unwrap())
+        .last()
+        .unwrap();
+
+    // Attempt to join with invalid ids
+    let join = forest.add_join(overflow, second);
+    assert_eq!(join, Err(MastForestError::InvalidNodeId(overflow)));
+    let join = forest.add_join(first, overflow);
+    assert_eq!(join, Err(MastForestError::InvalidNodeId(overflow)));
+
+    // Attempt to split with invalid ids
+    let split = forest.add_split(overflow, second);
+    assert_eq!(split, Err(MastForestError::InvalidNodeId(overflow)));
+    let split = forest.add_split(first, overflow);
+    assert_eq!(split, Err(MastForestError::InvalidNodeId(overflow)));
+
+    // Attempt to loop with invalid ids
+    assert_eq!(forest.add_loop(overflow), Err(MastForestError::InvalidNodeId(overflow)));
+
+    // Attempt to call with invalid ids
+    assert_eq!(forest.add_call(overflow), Err(MastForestError::InvalidNodeId(overflow)));
+    assert_eq!(forest.add_syscall(overflow), Err(MastForestError::InvalidNodeId(overflow)));
+
+    // Validate normal operations
+    forest.add_join(first, second).unwrap();
+}