diff --git a/src/flamenco/runtime/program/fd_zk_elgamal_proof_program.c b/src/flamenco/runtime/program/fd_zk_elgamal_proof_program.c
index 8adb65aebf..6a559e1661 100644
--- a/src/flamenco/runtime/program/fd_zk_elgamal_proof_program.c
+++ b/src/flamenco/runtime/program/fd_zk_elgamal_proof_program.c
@@ -9,6 +9,11 @@
 
 int
 fd_executor_zk_elgamal_proof_program_execute( fd_exec_instr_ctx_t * ctx ) {
+  /* Feature-gate program activation */
+  if( FD_UNLIKELY( !FD_FEATURE_ACTIVE( ctx->slot_ctx, zk_elgamal_proof_program_enabled ) ) ) {
+    return FD_EXECUTOR_INSTR_ERR_UNSUPPORTED_PROGRAM_ID;
+  }
+
   uchar const * instr_data    = ctx->instr->data;
   ulong         instr_data_sz = ctx->instr->data_sz;
 
diff --git a/src/flamenco/runtime/program/zksdk/fd_zksdk.c b/src/flamenco/runtime/program/zksdk/fd_zksdk.c
index 0e9088b63a..de58a4a756 100644
--- a/src/flamenco/runtime/program/zksdk/fd_zksdk.c
+++ b/src/flamenco/runtime/program/zksdk/fd_zksdk.c
@@ -161,6 +161,11 @@ fd_zksdk_process_verify_proof( fd_exec_instr_ctx_t * ctx ) {
   if( ctx->instr->data_sz == 5UL ) {
     /* Case 1. Proof data from account data. */
 
+    /* https://github.com/anza-xyz/agave/blob/v2.1.7/programs/zk-token-proof/src/lib.rs#L54-L59 */
+    if( FD_UNLIKELY( !FD_FEATURE_ACTIVE( ctx->slot_ctx, enable_zk_proof_from_account ) ) ) {
+      return FD_EXECUTOR_INSTR_ERR_INVALID_INSTR_DATA;
+    }
+
     /* https://github.com/anza-xyz/agave/blob/v2.0.1/programs/zk-elgamal-proof/src/lib.rs#L46-L47 */
     FD_BORROWED_ACCOUNT_DECL( proof_data_acc );
     FD_BORROWED_ACCOUNT_TRY_BORROW_IDX( ctx, 0UL, proof_data_acc ) {