diff --git a/src/erasurecode.c b/src/erasurecode.c
index 2d6d293..13e5f02 100644
--- a/src/erasurecode.c
+++ b/src/erasurecode.c
@@ -1025,6 +1025,11 @@ out:
 int liberasurecode_verify_fragment_metadata(ec_backend_t be,
                                             fragment_metadata_t *md)
 {
+    int k = be->args.uargs.k;
+    int m = be->args.uargs.m;
+    if (md->idx < 0 || (md->idx > (k + m))) {
+        return 1;
+    }
     if (md->backend_id != be->common.id) {
         return 1;
     }
diff --git a/test/liberasurecode_test.c b/test/liberasurecode_test.c
index b5239a9..e8b3179 100644
--- a/test/liberasurecode_test.c
+++ b/test/liberasurecode_test.c
@@ -265,6 +265,8 @@ typedef enum {
     MAGIC_MISMATCH,
     BACKEND_ID_MISMATCH,
     BACKEND_VERSION_MISMATCH,
+    FRAGIDX_INVALID,
+    FRAGIDX_OUT_OF_RANGE,
 } fragment_mismatch_scenario_t;
 
 char * get_name_from_backend_id(ec_backend_id_t be) {
@@ -1411,6 +1413,7 @@ static void verify_fragment_metadata_mismatch_impl(const ec_backend_id_t be_id,
     uint32_t orig_libec_ver = 0;
     uint32_t orig_be_ver = 0;
     uint8_t orig_be_id = 0;
+    uint32_t orig_frag_idx = 0;
     int *skip = create_skips_array(args,-1);
     char *orig_data = create_buffer(orig_data_size, 'x');
     int desc = liberasurecode_instance_create(be_id, args);
@@ -1428,7 +1431,7 @@ static void verify_fragment_metadata_mismatch_impl(const ec_backend_id_t be_id,
             encoded_parity, args, skip);
     for (i = 0; i < num_avail_frags; i++) {
         char * cur_frag = avail_frags[i];
-        //corrupt fragment
+        // corrupt fragment
         switch (scenario) {
             case LIBEC_VERSION_MISMATCH:
                 orig_libec_ver = ((fragment_header_t*)cur_frag)->libec_version;
@@ -1445,12 +1448,20 @@ static void verify_fragment_metadata_mismatch_impl(const ec_backend_id_t be_id,
                 orig_be_ver = ((fragment_header_t*)cur_frag)->meta.backend_version;
                 ((fragment_header_t*)cur_frag)->meta.backend_version = orig_be_ver + 1;
                 break;
+            case FRAGIDX_INVALID:
+                orig_frag_idx = ((fragment_header_t*)cur_frag)->meta.idx;
+                ((fragment_header_t*)cur_frag)->meta.idx = -1;
+                break;
+            case FRAGIDX_OUT_OF_RANGE:
+                orig_frag_idx = ((fragment_header_t*)cur_frag)->meta.idx;
+                ((fragment_header_t*)cur_frag)->meta.idx = args->k + args->m + 1;
+                break;
             default:
                 assert(false);
         }
         rc = is_invalid_fragment(desc, avail_frags[i]);
         assert(rc == 1);
-        //heal fragment
+        // heal fragment
         switch (scenario) {
             case LIBEC_VERSION_MISMATCH:
                 ((fragment_header_t*)cur_frag)->libec_version = orig_libec_ver;
@@ -1464,6 +1475,10 @@ static void verify_fragment_metadata_mismatch_impl(const ec_backend_id_t be_id,
             case BACKEND_VERSION_MISMATCH:
                 ((fragment_header_t*)cur_frag)->meta.backend_version = orig_be_ver;
                 break;
+            case FRAGIDX_INVALID:
+            case FRAGIDX_OUT_OF_RANGE:
+                ((fragment_header_t*)cur_frag)->meta.idx = orig_frag_idx;
+                break;
             default:
                 break;
         }
@@ -1496,6 +1511,13 @@ static void test_verify_stripe_metadata_be_ver_mismatch(
     verify_fragment_metadata_mismatch_impl(be_id, args, BACKEND_VERSION_MISMATCH);
 }
 
+static void test_verify_stripe_metadata_frag_idx_invalid(
+        const ec_backend_id_t be_id, struct ec_args *args)
+{
+    verify_fragment_metadata_mismatch_impl(be_id, args, FRAGIDX_INVALID);
+    verify_fragment_metadata_mismatch_impl(be_id, args, FRAGIDX_OUT_OF_RANGE);
+}
+
 
 //static void test_verify_str
 
@@ -1622,6 +1644,10 @@ struct testcase testcases[] = {
         test_verify_stripe_metadata_be_ver_mismatch,
         EC_BACKEND_FLAT_XOR_HD, CHKSUM_CRC32,
         .skip = false},
+    {"test_verify_stripe_metadata_frag_idx_invalid",
+        test_verify_stripe_metadata_frag_idx_invalid,
+        EC_BACKEND_FLAT_XOR_HD, CHKSUM_CRC32,
+        .skip = false},
     {"test_simple_encode_decode_over32",
         test_simple_encode_decode_over32,
         EC_BACKEND_JERASURE_RS_VAND, CHKSUM_CRC32,
@@ -1687,6 +1713,10 @@ struct testcase testcases[] = {
         test_verify_stripe_metadata_be_ver_mismatch,
         EC_BACKEND_JERASURE_RS_VAND, CHKSUM_CRC32,
         .skip = false},
+    {"test_verify_stripe_metadata_frag_idx_invalid",
+        test_verify_stripe_metadata_frag_idx_invalid,
+        EC_BACKEND_JERASURE_RS_VAND, CHKSUM_CRC32,
+        .skip = false},
     // Jerasure RS Cauchy backend tests
     {"create_and_destroy_backend",
         test_create_and_destroy_backend,
@@ -1748,6 +1778,10 @@ struct testcase testcases[] = {
         test_verify_stripe_metadata_be_ver_mismatch,
         EC_BACKEND_JERASURE_RS_CAUCHY, CHKSUM_CRC32,
         .skip = false},
+    {"test_verify_stripe_metadata_frag_idx_invalid",
+        test_verify_stripe_metadata_frag_idx_invalid,
+        EC_BACKEND_JERASURE_RS_CAUCHY, CHKSUM_CRC32,
+        .skip = false},
     // ISA-L tests
     {"create_and_destroy_backend",
         test_create_and_destroy_backend,
@@ -1805,6 +1839,10 @@ struct testcase testcases[] = {
         test_verify_stripe_metadata_be_ver_mismatch,
         EC_BACKEND_ISA_L_RS_VAND, CHKSUM_CRC32,
         .skip = false},
+    {"test_verify_stripe_metadata_frag_idx_invalid",
+        test_verify_stripe_metadata_frag_idx_invalid,
+        EC_BACKEND_ISA_L_RS_VAND, CHKSUM_CRC32,
+        .skip = false},
     // shss tests
     {"create_and_destroy_backend",
         test_create_and_destroy_backend,
@@ -1862,6 +1900,10 @@ struct testcase testcases[] = {
         test_verify_stripe_metadata_be_ver_mismatch,
         EC_BACKEND_SHSS, CHKSUM_CRC32,
         .skip = false},
+    {"test_verify_stripe_metadata_frag_idx_invalid",
+        test_verify_stripe_metadata_frag_idx_invalid,
+        EC_BACKEND_SHSS, CHKSUM_CRC32,
+        .skip = false},
     // Internal RS Vand backend tests
     {"create_and_destroy_backend",
         test_create_and_destroy_backend,
@@ -1923,6 +1965,10 @@ struct testcase testcases[] = {
         test_verify_stripe_metadata_be_ver_mismatch,
         EC_BACKEND_LIBERASURECODE_RS_VAND, CHKSUM_CRC32,
         .skip = false},
+    {"test_verify_stripe_metadata_frag_idx_invalid",
+        test_verify_stripe_metadata_frag_idx_invalid,
+        EC_BACKEND_LIBERASURECODE_RS_VAND, CHKSUM_CRC32,
+        .skip = false},
     { NULL, NULL, 0, 0, false },
 };