diff --git a/src/parser_yang.c b/src/parser_yang.c
index df9982906..e885034a9 100644
--- a/src/parser_yang.c
+++ b/src/parser_yang.c
@@ -2208,7 +2208,7 @@ parse_type_pattern_modifier(struct lysp_yang_ctx *ctx, struct lysp_restr *restr)
     /* replace the value in the dictionary */
     buf = malloc(strlen(restr->arg.str) + 1);
     LY_CHECK_ERR_GOTO(!buf, LOGMEM(PARSER_CTX(ctx)); ret = LY_EMEM, cleanup);
-    strcpy(buf, restr->arg.str);
+    memcpy(buf, restr->arg.str, strlen(restr->arg.str) + 1);
     lysdict_remove(PARSER_CTX(ctx), restr->arg.str);
 
     assert(buf[0] == LYSP_RESTR_PATTERN_ACK);
diff --git a/src/parser_yin.c b/src/parser_yin.c
index cf8890502..12f1046ea 100644
--- a/src/parser_yin.c
+++ b/src/parser_yin.c
@@ -1005,9 +1005,8 @@ yin_parse_modifier(struct lysp_yin_ctx *ctx, const void *parent, const char **pa
     lysdict_remove(ctx->xmlctx->ctx, temp_val);
 
     /* allocate new value */
-    modified_val = malloc(strlen(*pat) + 1);
+    modified_val = strdup(*pat);
     LY_CHECK_ERR_RET(!modified_val, LOGMEM(ctx->xmlctx->ctx), LY_EMEM);
-    strcpy(modified_val, *pat);
     lysdict_remove(ctx->xmlctx->ctx, *pat);
 
     /* modify the new value */
@@ -1994,7 +1993,7 @@ yin_parse_revision_date(struct lysp_yin_ctx *ctx, char *rev, struct lysp_ext_ins
     LY_CHECK_ERR_RET(lys_check_date(PARSER_CTX(ctx), temp_rev, strlen(temp_rev), "revision-date") != LY_SUCCESS,
             lysdict_remove(ctx->xmlctx->ctx, temp_rev), LY_EVALID);
 
-    strcpy(rev, temp_rev);
+    memcpy(rev, temp_rev, LY_REV_SIZE);
     lysdict_remove(ctx->xmlctx->ctx, temp_rev);
 
     LY_CHECK_RET(yin_parse_content(ctx, subelems, ly_sizeofarray(subelems), rev, LY_STMT_REVISION_DATE, NULL, exts));
diff --git a/src/plugins_exts/schema_mount.c b/src/plugins_exts/schema_mount.c
index 48723f6b9..f62b027a2 100644
--- a/src/plugins_exts/schema_mount.c
+++ b/src/plugins_exts/schema_mount.c
@@ -1522,12 +1522,14 @@ schema_mount_compiled_print(const struct lysc_ext_instance *orig_ext, struct lys
             sm_data->shared->schemas[i].ctx = ctx_mem;
 
             /* mount_point */
-            strcpy(*mem, orig_sm_data->shared->schemas[i].mount_point);
+            memcpy(*mem, orig_sm_data->shared->schemas[i].mount_point,
+                    strlen(orig_sm_data->shared->schemas[i].mount_point) + 1);
             sm_data->shared->schemas[i].mount_point = *mem;
             *mem = (char *)*mem + LY_CTXP_MEM_SIZE(strlen(sm_data->shared->schemas[i].mount_point) + 1);
 
             /* content_id */
-            strcpy(*mem, orig_sm_data->shared->schemas[i].content_id);
+            memcpy(*mem, orig_sm_data->shared->schemas[i].content_id,
+                    strlen(orig_sm_data->shared->schemas[i].content_id) + 1);
             sm_data->shared->schemas[i].content_id = *mem;
             *mem = (char *)*mem + LY_CTXP_MEM_SIZE(strlen(sm_data->shared->schemas[i].content_id) + 1);
         }
diff --git a/src/plugins_types/decimal64.c b/src/plugins_types/decimal64.c
index a678abfc8..bc5168535 100644
--- a/src/plugins_types/decimal64.c
+++ b/src/plugins_types/decimal64.c
@@ -53,14 +53,14 @@ decimal64_num2str(int64_t num, struct lysc_type_dec *type, char **str)
     LY_CHECK_RET(!ret, LY_EMEM);
 
     if (num) {
-        int count = sprintf(ret, "%" PRId64 " ", num);
+        int count = snprintf(ret, LY_NUMBER_MAXLEN, "%" PRId64 " ", num);
 
         if (((num > 0) && ((count - 1) <= type->fraction_digits)) || ((count - 2) <= type->fraction_digits)) {
             /* we have 0. value, print the value with the leading zeros
              * (one for 0. and also keep the correct with of num according
              * to fraction-digits value)
              * for (num < 0) - extra character for '-' sign */
-            count = sprintf(ret, "%0*" PRId64 " ", (num > 0) ? (type->fraction_digits + 1) : (type->fraction_digits + 2), num);
+            count = snprintf(ret, LY_NUMBER_MAXLEN, "%0*" PRId64 " ", (num > 0) ? (type->fraction_digits + 1) : (type->fraction_digits + 2), num);
         }
         for (uint8_t i = type->fraction_digits, j = 1; i > 0; i--) {
             if (j && (i > 1) && (ret[count - 2] == '0')) {
@@ -75,7 +75,7 @@ decimal64_num2str(int64_t num, struct lysc_type_dec *type, char **str)
         ret[count - 1] = '.';
     } else {
         /* zero */
-        sprintf(ret, "0.0");
+        snprintf(ret, LY_NUMBER_MAXLEN, "0.0");
     }
 
     *str = ret;
diff --git a/src/plugins_types/ipv4_address_prefix.c b/src/plugins_types/ipv4_address_prefix.c
index 350b1a3ae..150e867ac 100644
--- a/src/plugins_types/ipv4_address_prefix.c
+++ b/src/plugins_types/ipv4_address_prefix.c
@@ -275,7 +275,7 @@ lyplg_type_print_ipv4_address_prefix(const struct ly_ctx *ctx, const struct lyd_
         }
 
         /* add the prefix */
-        sprintf(ret + strlen(ret), "/%" PRIu8, val->prefix);
+        snprintf(ret + strlen(ret), INET_ADDRSTRLEN + 4 - strlen(ret), "/%" PRIu8, val->prefix);
 
         /* store it */
         if (lydict_insert_zc(ctx, ret, (const char **)&value->_canonical)) {
diff --git a/src/plugins_types/ipv6_address_prefix.c b/src/plugins_types/ipv6_address_prefix.c
index bf9f828f9..2bdcce8a2 100644
--- a/src/plugins_types/ipv6_address_prefix.c
+++ b/src/plugins_types/ipv6_address_prefix.c
@@ -289,7 +289,7 @@ lyplg_type_print_ipv6_address_prefix(const struct ly_ctx *ctx, const struct lyd_
         }
 
         /* add the prefix */
-        sprintf(ret + strlen(ret), "/%" PRIu8, val->prefix);
+        snprintf(ret + strlen(ret), INET6_ADDRSTRLEN + 4 - strlen(ret), "/%" PRIu8, val->prefix);
 
         /* store it */
         if (lydict_insert_zc(ctx, ret, (const char **)&value->_canonical)) {
diff --git a/src/schema_diff_tree.c b/src/schema_diff_tree.c
index 82cce7b69..3c0089d6d 100644
--- a/src/schema_diff_tree.c
+++ b/src/schema_diff_tree.c
@@ -316,7 +316,7 @@ schema_diff_pnode_path(const struct lysp_node *node)
         path = ly_realloc(path, new_len + 1);
         LY_CHECK_ERR_GOTO(!path, LOGMEM(NULL), cleanup);
 
-        sprintf(path + path_len, "/%s%s%s", node_pre ? node_pre : "", nodes[i]->name, node_post ? node_post : "");
+        snprintf(path + path_len, new_len + 1 - path_len, "/%s%s%s", node_pre ? node_pre : "", nodes[i]->name, node_post ? node_post : "");
         path_len = new_len;
     } while (i);
 
@@ -491,11 +491,11 @@ schema_diff_ext_inst_substmts_bitenums(const struct ly_ctx *ctx, const struct ly
 
         /* value/position */
         if (items[u].flags & LYS_IS_ENUM) {
-            sprintf(num_str, "%" PRId32, items[u].value);
+            snprintf(num_str, sizeof num_str, "%" PRId32, items[u].value);
             LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, "value", num_str, &bitenum_node->child),
                     cleanup);
         } else {
-            sprintf(num_str, "%" PRIu32, items[u].position);
+            snprintf(num_str, sizeof num_str, "%" PRIu32, items[u].position);
             LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, "position", num_str, &bitenum_node->child),
                     cleanup);
         }
@@ -611,16 +611,16 @@ schema_diff_range2str(struct lysc_range_part *parts, ly_bool is_signed, char **s
 
     LYA_FOR(parts, u) {
         if (is_signed) {
-            sprintf(num_min_str, "%" PRId64, parts[u].min_64);
+            snprintf(num_min_str, sizeof num_min_str, "%" PRId64, parts[u].min_64);
             if (parts[u].min_64 < parts[u].max_64) {
-                sprintf(num_max_str, "%" PRId64, parts[u].max_64);
+                snprintf(num_max_str, sizeof num_max_str, "%" PRId64, parts[u].max_64);
             } else {
                 num_max_str[0] = '\0';
             }
         } else {
-            sprintf(num_min_str, "%" PRIu64, parts[u].min_u64);
+            snprintf(num_min_str, sizeof num_min_str, "%" PRIu64, parts[u].min_u64);
             if (parts[u].min_u64 < parts[u].max_u64) {
-                sprintf(num_max_str, "%" PRIu64, parts[u].max_u64);
+                snprintf(num_max_str, sizeof num_max_str, "%" PRIu64, parts[u].max_u64);
             } else {
                 num_max_str[0] = '\0';
             }
@@ -630,7 +630,7 @@ schema_diff_range2str(struct lysc_range_part *parts, ly_bool is_signed, char **s
         s = ly_realloc(s, new_len + 1);
         LY_CHECK_ERR_GOTO(!s, LOGMEM(NULL); rc = LY_EMEM, cleanup);
 
-        sprintf(s + s_len, "%s%s%s%s", s_len ? "|" : "", num_min_str, num_max_str[0] ? ".." : "",
+        snprintf(s + s_len, new_len + 1 - s_len, "%s%s%s%s", s_len ? "|" : "", num_min_str, num_max_str[0] ? ".." : "",
                 num_max_str[0] ? num_max_str : "");
         s_len = new_len;
     }
@@ -877,7 +877,7 @@ schema_diff_ext_inst_substmts_type(const struct ly_ctx *ctx, const struct lysc_t
         type_dec = (const struct lysc_type_dec *)type;
 
         /* fraction-digits */
-        sprintf(num_str, "%" PRIu8, type_dec->fraction_digits);
+        snprintf(num_str, sizeof num_str, "%" PRIu8, type_dec->fraction_digits);
         LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, "fraction-digits", num_str, child_p), cleanup);
 
         /* range */
@@ -1099,12 +1099,12 @@ schema_diff_ext_inst_substmts_nodes_r(const struct lysc_node *sibling, struct ly
             max = llist->max;
         }
         if (min > 0) {
-            sprintf(num_str, "%" PRIu32, min);
+            snprintf(num_str, sizeof num_str, "%" PRIu32, min);
             LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, "min-elements", num_str, &node->child),
                     cleanup);
         }
         if (max < UINT32_MAX) {
-            sprintf(num_str, "%" PRIu32, max);
+            snprintf(num_str, sizeof num_str, "%" PRIu32, max);
             LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, "max-elements", num_str, &node->child),
                     cleanup);
         }
@@ -1221,7 +1221,7 @@ schema_diff_ext_inst_substmts(const struct ly_ctx *ctx, const struct lysc_ext_su
 
             /* uint8 number */
             if (*(substmts[u].storage_p)) {
-                sprintf(num_str, "%" PRIu8, *(uint8_t *)substmts[u].storage_p);
+                snprintf(num_str, sizeof num_str, "%" PRIu8, *(uint8_t *)substmts[u].storage_p);
                 LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, lys_stmt_str(substmts[u].stmt), num_str,
                         child_p), cleanup);
             }
@@ -1253,7 +1253,7 @@ schema_diff_ext_inst_substmts(const struct ly_ctx *ctx, const struct lysc_ext_su
 
             /* uint32 number */
             if (*(uint32_t *)substmts[u].storage_p < UINT32_MAX) {
-                sprintf(num_str, "%" PRIu32, *(uint32_t *)substmts[u].storage_p);
+                snprintf(num_str, sizeof num_str, "%" PRIu32, *(uint32_t *)substmts[u].storage_p);
                 LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, "max-elements", num_str, child_p),
                         cleanup);
             }
@@ -1264,7 +1264,7 @@ schema_diff_ext_inst_substmts(const struct ly_ctx *ctx, const struct lysc_ext_su
 
             /* uint32 number */
             if (*(uint32_t *)substmts[u].storage_p > 0) {
-                sprintf(num_str, "%" PRIu32, *(uint32_t *)substmts[u].storage_p);
+                snprintf(num_str, sizeof num_str, "%" PRIu32, *(uint32_t *)substmts[u].storage_p);
                 LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, "min-elements", num_str, child_p),
                         cleanup);
             }
@@ -1290,7 +1290,7 @@ schema_diff_ext_inst_substmts(const struct ly_ctx *ctx, const struct lysc_ext_su
             char num_str[21];
 
             /* uint64 number */
-            sprintf(num_str, "%" PRIu64, *(uint64_t *)substmts[u].storage_p);
+            snprintf(num_str, sizeof num_str, "%" PRIu64, *(uint64_t *)substmts[u].storage_p);
             LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, "position", num_str, child_p), cleanup);
             break;
         }
@@ -1334,7 +1334,7 @@ schema_diff_ext_inst_substmts(const struct ly_ctx *ctx, const struct lysc_ext_su
             char num_str[21];
 
             /* int64 number */
-            sprintf(num_str, "%" PRId64, *(int64_t *)substmts[u].storage_p);
+            snprintf(num_str, sizeof num_str, "%" PRId64, *(int64_t *)substmts[u].storage_p);
             LY_CHECK_GOTO(rc = schema_diff_ext_inst_substmts_child_add(ctx, "value", num_str, child_p), cleanup);
             break;
         }
@@ -1958,11 +1958,11 @@ schema_diff_parsed_enum(const struct lysp_type_enum *enm, ly_bool is_bit, struct
 
     if (is_bit) {
         /* position */
-        sprintf(str, "%" PRIu64, (uint64_t)enm->value);
+        snprintf(str, sizeof str, "%" PRIu64, (uint64_t)enm->value);
         LY_CHECK_GOTO(rc = lyd_new_term(enum_list, NULL, "position", str, LYD_NEW_VAL_CANON, NULL), cleanup);
     } else {
         /* value */
-        sprintf(str, "%" PRId64, enm->value);
+        snprintf(str, sizeof str, "%" PRId64, enm->value);
         LY_CHECK_GOTO(rc = lyd_new_term(enum_list, NULL, "value", str, LYD_NEW_VAL_CANON, NULL), cleanup);
     }
 
@@ -2011,7 +2011,7 @@ schema_diff_parsed_type(const struct lysp_type *type, struct lyd_node *cont)
 
     /* fraction-digits */
     if (type->flags & LYS_SET_FRDIGITS) {
-        sprintf(str, "%" PRIu8, type->fraction_digits);
+        snprintf(str, sizeof str, "%" PRIu8, type->fraction_digits);
         LY_CHECK_GOTO(rc = lyd_new_term(cont, NULL, "fraction-digits", str, LYD_NEW_VAL_CANON, NULL), cleanup);
     }
 
@@ -2264,7 +2264,7 @@ schema_diff_pnode(const struct lysp_node *pnode, struct lyd_node *change_cont)
 
     /* min-elements */
     if (min_set) {
-        sprintf(buf, "%" PRIu32, min);
+        snprintf(buf, sizeof buf, "%" PRIu32, min);
         if ((rc = lyd_new_term(change_cont, NULL, "min-elements", buf, 0, NULL))) {
             goto cleanup;
         }
@@ -2272,7 +2272,7 @@ schema_diff_pnode(const struct lysp_node *pnode, struct lyd_node *change_cont)
 
     /* max-elements */
     if (max_set) {
-        sprintf(buf, "%" PRIu32, max);
+        snprintf(buf, sizeof buf, "%" PRIu32, max);
         if ((rc = lyd_new_term(change_cont, NULL, "max-elements", buf, 0, NULL))) {
             goto cleanup;
         }
@@ -2405,7 +2405,7 @@ schema_diff_refine(const struct lysp_refine *refine, struct lyd_node *change_con
 
     /* min-elements */
     if (refine->flags & LYS_SET_MIN) {
-        sprintf(buf, "%" PRIu32, refine->min);
+        snprintf(buf, sizeof buf, "%" PRIu32, refine->min);
         if ((rc = lyd_new_term(change_cont, NULL, "min-elements", buf, 0, NULL))) {
             goto cleanup;
         }
@@ -2413,7 +2413,7 @@ schema_diff_refine(const struct lysp_refine *refine, struct lyd_node *change_con
 
     /* max-elements */
     if (refine->flags & LYS_SET_MAX) {
-        sprintf(buf, "%" PRIu32, refine->max);
+        snprintf(buf, sizeof buf, "%" PRIu32, refine->max);
         if ((rc = lyd_new_term(change_cont, NULL, "max-elements", buf, 0, NULL))) {
             goto cleanup;
         }
@@ -3122,7 +3122,7 @@ schema_diff_deviation(const struct lysp_deviation *dev, struct lyd_node *change_
 
         /* min-elements */
         if (flags & LYS_SET_MIN) {
-            sprintf(buf, "%" PRIu32, min);
+            snprintf(buf, sizeof buf, "%" PRIu32, min);
             if ((rc = lyd_new_term(dev_list, NULL, "min-elements", buf, 0, NULL))) {
                 goto cleanup;
             }
@@ -3130,7 +3130,7 @@ schema_diff_deviation(const struct lysp_deviation *dev, struct lyd_node *change_
 
         /* max-elements */
         if (flags & LYS_SET_MAX) {
-            sprintf(buf, "%" PRIu32, max);
+            snprintf(buf, sizeof buf, "%" PRIu32, max);
             if ((rc = lyd_new_term(dev_list, NULL, "max-elements", buf, 0, NULL))) {
                 goto cleanup;
             }
@@ -3523,10 +3523,10 @@ schema_diff_node_type_bitenums(const struct lysc_type_bitenum_item *items, struc
 
         /* value/position */
         if (items[u].flags & LYS_IS_ENUM) {
-            sprintf(buf, "%" PRId32, items[u].value);
+            snprintf(buf, sizeof buf, "%" PRId32, items[u].value);
             LY_CHECK_GOTO(rc = lyd_new_term(par_list, NULL, "value", buf, 0, NULL), cleanup);
         } else {
-            sprintf(buf, "%" PRIu32, items[u].position);
+            snprintf(buf, sizeof buf, "%" PRIu32, items[u].position);
             LY_CHECK_GOTO(rc = lyd_new_term(par_list, NULL, "position", buf, 0, NULL), cleanup);
         }
 
@@ -3625,7 +3625,7 @@ schema_diff_node_type(const struct lysc_type *type, struct lyd_node *type_par)
         type_dec = (const struct lysc_type_dec *)type;
 
         /* fraction-digits */
-        sprintf(buf, "%" PRIu8, type_dec->fraction_digits);
+        snprintf(buf, sizeof buf, "%" PRIu8, type_dec->fraction_digits);
         LY_CHECK_GOTO(rc = lyd_new_term(type_par, NULL, "fraction-digits", buf, 0, NULL), cleanup);
 
         /* range */
@@ -3828,13 +3828,13 @@ schema_diff_node_stmts(const struct lysc_node *node, ly_bool gen_local, struct l
         max = llist->max;
     }
     if (min > 0) {
-        sprintf(buf, "%" PRIu32, min);
+        snprintf(buf, sizeof buf, "%" PRIu32, min);
         if ((rc = lyd_new_term(change_cont, NULL, "min-elements", buf, 0, NULL))) {
             goto cleanup;
         }
     }
     if (max < UINT32_MAX) {
-        sprintf(buf, "%" PRIu32, max);
+        snprintf(buf, sizeof buf, "%" PRIu32, max);
         if ((rc = lyd_new_term(change_cont, NULL, "max-elements", buf, 0, NULL))) {
             goto cleanup;
         }
diff --git a/src/tree_data_common.c b/src/tree_data_common.c
index 9fc0159d0..6089b6559 100644
--- a/src/tree_data_common.c
+++ b/src/tree_data_common.c
@@ -1648,7 +1648,7 @@ ly_time_time2str(time_t time, const char *fractions_s, char **str)
     zonediff_s = ly_time_tz_offset_at(time);
     zonediff_h = zonediff_s / 60 / 60;
     zonediff_m = zonediff_s / 60 % 60;
-    sprintf(zoneshift, "%+03d:%02d", zonediff_h, zonediff_m < 0 ? -zonediff_m : zonediff_m);
+    snprintf(zoneshift, sizeof zoneshift, "%+03d:%02d", zonediff_h, zonediff_m < 0 ? -zonediff_m : zonediff_m);
 
     /* print */
     if (asprintf(str, "%04d-%02d-%02dT%02d:%02d:%02d%s%s%s",
@@ -1698,7 +1698,7 @@ ly_time_ts2str(const struct timespec *ts, char **str)
 
     /* convert nanoseconds to fractions of a second */
     if (ts->tv_nsec) {
-        sprintf(frac_buf, "%09ld", ts->tv_nsec);
+        snprintf(frac_buf, sizeof frac_buf, "%09ld", ts->tv_nsec);
     }
 
     return ly_time_time2str(ts->tv_sec, ts->tv_nsec ? frac_buf : NULL, str);
diff --git a/src/tree_schema.c b/src/tree_schema.c
index 85b8833fa..bcf0f17ae 100644
--- a/src/tree_schema.c
+++ b/src/tree_schema.c
@@ -1000,7 +1000,7 @@ lysc_path_until(const struct lysc_node *node, const struct lysc_node *parent, LY
         path = NULL;
     } else if (len == 0) {
         if (buffer) {
-            strcpy(buffer, "/");
+            snprintf(buffer, buflen, "/");
         } else {
             free(path);
             path = strdup("/");
diff --git a/src/validation.c b/src/validation.c
index 850bb0c67..babc112d0 100644
--- a/src/validation.c
+++ b/src/validation.c
@@ -1578,7 +1578,7 @@ lyd_val_uniq_list_equal(void *val1_p, void *val2_p, ly_bool UNUSED(mod), void *c
             ptr = uniq_str;
             LYA_FOR(slist->uniques[u], v) {
                 if (v) {
-                    strcpy(ptr, " ");
+                    memcpy(ptr, " ", 2);
                     ++ptr;
                 }
                 ptr = lysc_path_until((struct lysc_node *)slist->uniques[u][v], &slist->node, LYSC_PATH_LOG,