diff --git a/specs/deneb/p2p-interface.md b/specs/deneb/p2p-interface.md
index 107c90b9a..84e0f1959 100644
--- a/specs/deneb/p2p-interface.md
+++ b/specs/deneb/p2p-interface.md
@@ -112,6 +112,7 @@ The following validations MUST pass before forwarding the `sidecar` on the netwo
 - _[IGNORE]_ The sidecar is from a slot greater than the latest finalized slot -- i.e. validate that `sidecar.slot > compute_start_slot_at_epoch(state.finalized_checkpoint.epoch)`
 - _[IGNORE]_ The sidecar's block's parent (defined by `sidecar.block_parent_root`) has been seen (via both gossip and non-gossip sources) (a client MAY queue sidecars for processing once the parent block is retrieved).
 - _[REJECT]_ The sidecar's block's parent (defined by `sidecar.block_parent_root`) passes validation.
+- _[REJECT]_ The sidecar is from a higher slot than the sidecar's block's parent (defined by `sidecar.block_parent_root`).
 - _[REJECT]_ The proposer signature, `signed_blob_sidecar.signature`, is valid with respect to the `sidecar.proposer_index` pubkey.
 - _[IGNORE]_ The sidecar is the only sidecar with valid signature received for the tuple `(sidecar.block_root, sidecar.index)`.
 - _[REJECT]_ The sidecar is proposed by the expected `proposer_index` for the block's slot in the context of the current shuffling (defined by `block_parent_root`/`slot`).