diff --git a/src/flamenco/runtime/tests/fd_exec_instr_test.c b/src/flamenco/runtime/tests/fd_exec_instr_test.c
index 20c3041636..a84eca1522 100644
--- a/src/flamenco/runtime/tests/fd_exec_instr_test.c
+++ b/src/flamenco/runtime/tests/fd_exec_instr_test.c
@@ -899,8 +899,28 @@ fd_sbpf_program_load_test_run( fd_exec_test_elf_loader_ctx_t const * input,
     return 0UL;
   }
   
-  ulong elf_sz = input->elf.data->size;
-  void const * _bin = input->elf.data->bytes;
+  ulong elf_sz = input->elf_sz;
+  void const * _bin;
+
+  /* elf_sz will be passed as arguments to elf loader functions.
+     pb decoder allocates memory for elf.data based on its actual size,
+     not elf_sz !. 
+     If elf_sz is larger than the size of actual elf data, this may result
+     in out-of-bounds accesses which will upset ASAN (however intentional).
+     So in this case we just copy the data into a memory region of elf_sz bytes 
+     
+     ! The decoupling of elf_sz and the actual binary size is intentional to test
+      underflow/overflow behavior */
+  if ( elf_sz > input->elf.data->size ){
+    void * tmp = fd_valloc_malloc( valloc, 1UL, elf_sz );
+    if ( FD_UNLIKELY( !tmp ) ){
+      return 0UL;
+    }
+    fd_memcpy( tmp, input->elf.data->bytes, input->elf.data->size );
+    _bin = tmp;
+  } else {
+    _bin = input->elf.data->bytes;
+  }
 
   // Allocate space for captured effects
   ulong output_end = (ulong)output_buf + output_bufsz;
diff --git a/src/flamenco/runtime/tests/fd_exec_test.pb.h b/src/flamenco/runtime/tests/fd_exec_test.pb.h
index c309a6c4e6..cce3f4c4ef 100644
--- a/src/flamenco/runtime/tests/fd_exec_test.pb.h
+++ b/src/flamenco/runtime/tests/fd_exec_test.pb.h
@@ -130,6 +130,7 @@ typedef struct fd_exec_test_elf_loader_ctx {
     fd_exec_test_elf_binary_t elf;
     bool has_features;
     fd_exec_test_feature_set_t features;
+    uint64_t elf_sz;
 } fd_exec_test_elf_loader_ctx_t;
 
 /* Captures the results of a elf binary load.
@@ -169,7 +170,7 @@ extern "C" {
 #define FD_EXEC_TEST_INSTR_EFFECTS_INIT_DEFAULT  {0, false, 0, 0, NULL, 0, NULL}
 #define FD_EXEC_TEST_INSTR_FIXTURE_INIT_DEFAULT  {false, FD_EXEC_TEST_INSTR_CONTEXT_INIT_DEFAULT, false, FD_EXEC_TEST_INSTR_EFFECTS_INIT_DEFAULT}
 #define FD_EXEC_TEST_ELF_BINARY_INIT_DEFAULT     {NULL}
-#define FD_EXEC_TEST_ELF_LOADER_CTX_INIT_DEFAULT {false, FD_EXEC_TEST_ELF_BINARY_INIT_DEFAULT, false, FD_EXEC_TEST_FEATURE_SET_INIT_DEFAULT}
+#define FD_EXEC_TEST_ELF_LOADER_CTX_INIT_DEFAULT {false, FD_EXEC_TEST_ELF_BINARY_INIT_DEFAULT, false, FD_EXEC_TEST_FEATURE_SET_INIT_DEFAULT, 0}
 #define FD_EXEC_TEST_ELF_LOADER_EFFECTS_INIT_DEFAULT {NULL, 0, 0, 0, 0, 0, NULL}
 #define FD_EXEC_TEST_ELF_LOADER_FIXTURE_INIT_DEFAULT {false, FD_EXEC_TEST_ELF_LOADER_CTX_INIT_DEFAULT, false, FD_EXEC_TEST_ELF_LOADER_EFFECTS_INIT_DEFAULT}
 #define FD_EXEC_TEST_FEATURE_SET_INIT_ZERO       {0, NULL}
@@ -182,7 +183,7 @@ extern "C" {
 #define FD_EXEC_TEST_INSTR_EFFECTS_INIT_ZERO     {0, false, 0, 0, NULL, 0, NULL}
 #define FD_EXEC_TEST_INSTR_FIXTURE_INIT_ZERO     {false, FD_EXEC_TEST_INSTR_CONTEXT_INIT_ZERO, false, FD_EXEC_TEST_INSTR_EFFECTS_INIT_ZERO}
 #define FD_EXEC_TEST_ELF_BINARY_INIT_ZERO        {NULL}
-#define FD_EXEC_TEST_ELF_LOADER_CTX_INIT_ZERO    {false, FD_EXEC_TEST_ELF_BINARY_INIT_ZERO, false, FD_EXEC_TEST_FEATURE_SET_INIT_ZERO}
+#define FD_EXEC_TEST_ELF_LOADER_CTX_INIT_ZERO    {false, FD_EXEC_TEST_ELF_BINARY_INIT_ZERO, false, FD_EXEC_TEST_FEATURE_SET_INIT_ZERO, 0}
 #define FD_EXEC_TEST_ELF_LOADER_EFFECTS_INIT_ZERO {NULL, 0, 0, 0, 0, 0, NULL}
 #define FD_EXEC_TEST_ELF_LOADER_FIXTURE_INIT_ZERO {false, FD_EXEC_TEST_ELF_LOADER_CTX_INIT_ZERO, false, FD_EXEC_TEST_ELF_LOADER_EFFECTS_INIT_ZERO}
 
@@ -217,6 +218,7 @@ extern "C" {
 #define FD_EXEC_TEST_ELF_BINARY_DATA_TAG         1
 #define FD_EXEC_TEST_ELF_LOADER_CTX_ELF_TAG      1
 #define FD_EXEC_TEST_ELF_LOADER_CTX_FEATURES_TAG 2
+#define FD_EXEC_TEST_ELF_LOADER_CTX_ELF_SZ_TAG   3
 #define FD_EXEC_TEST_ELF_LOADER_EFFECTS_RODATA_TAG 1
 #define FD_EXEC_TEST_ELF_LOADER_EFFECTS_RODATA_SZ_TAG 2
 #define FD_EXEC_TEST_ELF_LOADER_EFFECTS_TEXT_CNT_TAG 4
@@ -308,7 +310,8 @@ X(a, POINTER,  SINGULAR, BYTES,    data,              1)
 
 #define FD_EXEC_TEST_ELF_LOADER_CTX_FIELDLIST(X, a) \
 X(a, STATIC,   OPTIONAL, MESSAGE,  elf,               1) \
-X(a, STATIC,   OPTIONAL, MESSAGE,  features,          2)
+X(a, STATIC,   OPTIONAL, MESSAGE,  features,          2) \
+X(a, STATIC,   SINGULAR, UINT64,   elf_sz,            3)
 #define FD_EXEC_TEST_ELF_LOADER_CTX_CALLBACK NULL
 #define FD_EXEC_TEST_ELF_LOADER_CTX_DEFAULT NULL
 #define fd_exec_test_elf_loader_ctx_t_elf_MSGTYPE fd_exec_test_elf_binary_t
@@ -401,9 +404,12 @@ extern const pb_msgdesc_t fd_exec_test_elf_loader_fixture_t_msg;
 #define ORG_SOLANA_SEALEVEL_V1_INSTR_EFFECTS_INIT_DEFAULT FD_EXEC_TEST_INSTR_EFFECTS_INIT_DEFAULT
 #define ORG_SOLANA_SEALEVEL_V1_INSTR_FIXTURE_INIT_DEFAULT FD_EXEC_TEST_INSTR_FIXTURE_INIT_DEFAULT
 #define ORG_SOLANA_SEALEVEL_V1_ELF_BINARY_INIT_DEFAULT FD_EXEC_TEST_ELF_BINARY_INIT_DEFAULT
+#define ORG_SOLANA_SEALEVEL_V1_ELF_LOADER_CTX_INIT_DEFAULT FD_EXEC_TEST_ELF_LOADER_CTX_INIT_DEFAULT
+#define ORG_SOLANA_SEALEVEL_V1_ELF_LOADER_EFFECTS_INIT_DEFAULT FD_EXEC_TEST_ELF_LOADER_EFFECTS_INIT_DEFAULT
 #define ORG_SOLANA_SEALEVEL_V1_ELF_LOADER_FIXTURE_INIT_DEFAULT FD_EXEC_TEST_ELF_LOADER_FIXTURE_INIT_DEFAULT
 #define ORG_SOLANA_SEALEVEL_V1_FEATURE_SET_INIT_ZERO FD_EXEC_TEST_FEATURE_SET_INIT_ZERO
 #define ORG_SOLANA_SEALEVEL_V1_ACCT_STATE_INIT_ZERO FD_EXEC_TEST_ACCT_STATE_INIT_ZERO
+#define ORG_SOLANA_SEALEVEL_V1_EPOCH_CONTEXT_INIT_ZERO FD_EXEC_TEST_EPOCH_CONTEXT_INIT_ZERO
 #define ORG_SOLANA_SEALEVEL_V1_SLOT_CONTEXT_INIT_ZERO FD_EXEC_TEST_SLOT_CONTEXT_INIT_ZERO
 #define ORG_SOLANA_SEALEVEL_V1_TXN_CONTEXT_INIT_ZERO FD_EXEC_TEST_TXN_CONTEXT_INIT_ZERO
 #define ORG_SOLANA_SEALEVEL_V1_INSTR_ACCT_INIT_ZERO FD_EXEC_TEST_INSTR_ACCT_INIT_ZERO
diff --git a/src/flamenco/runtime/tests/fd_exec_test.proto b/src/flamenco/runtime/tests/fd_exec_test.proto
index f4b03bbde3..6faca681ae 100644
--- a/src/flamenco/runtime/tests/fd_exec_test.proto
+++ b/src/flamenco/runtime/tests/fd_exec_test.proto
@@ -124,6 +124,7 @@ message ELFBinary {
 message ELFLoaderCtx {
     ELFBinary elf = 1;
     FeatureSet features = 2;
+    uint64 elf_sz = 3;
 }
 
 // Captures the results of a elf binary load.