diff --git a/devel/214_10.md b/devel/214_10.md
new file mode 100644
index 00000000..eb099fe1
--- /dev/null
+++ b/devel/214_10.md
@@ -0,0 +1,75 @@
+# [214_10]
+
+## 任务相关的代码文件
+- src/goldfish.hpp
+- tests/goldfish/liii/njson-test.scm
+- devel/214_10.md
+
+## 如何测试
+```bash
+xmake b goldfish
+bin/goldfish tests/goldfish/liii/njson-test.scm
+bin/goldfish bench/njson-bench.scm
+```
+
+## 2026/3/2 修复 njson 句柄安全、set 写入语义与数值边界问题
+
+### What
+1. 修复句柄安全漏洞：
+   - 句柄从 `(njson-handle . id)` 升级为 `(njson-handle . (id . generation))`；
+   - 新增 `njson_handle_generations` 代际表，句柄校验必须同时匹配 `id + generation`；
+   - free-list 复用槽位时，`generation` 自增，旧句柄自动失效。
+2. 修复 `set/set!` 在“目标 parent 为标量”时静默 no-op 的问题：
+   - object/array 上原有行为保持不变（object upsert、array 仅允许已存在索引覆盖）；
+   - 当根或中间路径命中标量时，不再“成功返回但不生效”；
+   - 非容器 parent 现在统一抛 `key-error`；
+   - 错误消息：`set target must be array or object`。
+3. 收紧数值输入语义：
+   - 拒绝非有限实数（`NaN/+Inf/-Inf`）；
+   - 拒绝复数等“非 real number”输入；
+   - 防止“内存是 number，序列化变 null”的静默漂移。
+4. 测试增强：
+   - 增加 stale handle/伪造 handle/重复 free 防回归用例；
+   - 增加 `njson->string`、`set/set!`、`append/append!` 对 `NaN/Inf/complex` 的错误断言；
+   - 同步更新测试注释中的句柄结构说明。
+
+### Why
+1. 仅靠 `id` 的句柄在槽位复用时会产生“旧句柄复活”问题，进一步导致误释放新对象，存在明显安全风险。
+2. `set/set!` 对标量 parent 的静默成功会造成“写入看似成功、实际无变化”的数据一致性风险，排查成本高。
+3. JSON 标准不接受 `NaN/Inf`，若输入端接受而输出端转换为 `null`，会造成难以发现的语义漂移。
+4. 需要让 njson 的错误模型在句柄生命周期、路径写入和数值边界上都保持可预测、可测试、可回归。
+
+### How
+1. 句柄代际机制：
+   - `make_njson_handle` 输出 `(tag . (id . generation))`；
+   - `is_njson_handle`/`extract_njson_handle_id` 解析并校验 generation；
+   - 校验失败时明确区分：非法 generation、句柄不存在、stale handle mismatch。
+2. 槽位复用逻辑：
+   - 新增 `njson_ensure_generations_size`；
+   - `store_njson_value` 在复用 free id 时先递增 generation，再写入 JSON；
+   - 新分配槽位 generation 初始化为 `1`。
+3. `set/set!` 非容器 parent 行为修正：
+   - 在 `njson_apply_update_on_root` 的 `set` 分支补充非容器错误返回，避免 no-op；
+   - 覆盖两类场景：`(set scalar-root key value)` 与 `(set obj \"k\" \"x\" value)`（其中 `obj.k` 为标量）。
+4. 数值边界修正：
+   - `scheme_to_njson_scalar_or_handle` 区分 `real` 与 `number`；
+   - `real` 需 `std::isfinite`；
+   - 非 real 的 number 直接拒绝。
+5. 测试层回归：
+   - 新增 stale-handle 与 forged-handle 负例；
+   - 新增 finite number 约束的错误类型+错误消息断言；
+   - 保证行为变更均由测试锁定。
+
+### 兼容性说明
+1. 句柄内部形态变化：从 `(njson-handle . id)` 变为 `(njson-handle . (id . generation))`。
+2. 历史句柄在槽位复用后不再可用，会报 `generation mismatch (stale handle)`。
+3. `(cons 'njson-handle 1)` 这类旧伪造结构不再可通过句柄校验。
+4. `njson-set` / `njson-set!` 对标量 parent 现在会抛 `key-error`，不再静默 no-op。
+   - 典型错误消息：`g_njson-set: set target must be array or object`、`g_njson-set!: set target must be array or object`。
+5. `njson->string`、`set/set!`、`append/append!` 对 `NaN/Inf/complex` 输入会抛 `type-error`。
+
+## 验证结果
+本次文档编写前已执行：
+1. ✅ `xmake b goldfish` 通过。
+2. ✅ `bin/goldfish tests/goldfish/liii/njson-test.scm` 通过（`; *** checks *** : 336 correct, 0 failed.`）。
+3. ✅ `bin/goldfish bench/njson-bench.scm` 通过（`; *** checks *** : 29 correct, 0 failed.`）。
diff --git a/src/goldfish.hpp b/src/goldfish.hpp
index cc4326bc..76cf8b26 100644
--- a/src/goldfish.hpp
+++ b/src/goldfish.hpp
@@ -17,6 +17,7 @@
 #include <algorithm>
 #include <argh.h>
 #include <chrono>
+#include <cmath>
 #include <cstdint>
 #include <cstdlib>
 #include <cstring>
@@ -87,6 +88,7 @@ glue_define (s7_scheme* sc, const char* name, const char* desc, s7_function f, s
 
 static const char* NJSON_HANDLE_TAG = "njson-handle";
 static std::vector<std::unique_ptr<json>> njson_handle_store = std::vector<std::unique_ptr<json>> (1);
+static std::vector<s7_int> njson_handle_generations = std::vector<s7_int> (1, 0);
 static std::vector<s7_int> njson_handle_free_ids;
 static std::vector<s7_pointer> njson_keys_cache_values = std::vector<s7_pointer> (1, nullptr);
 static std::vector<s7_int> njson_keys_cache_gc_locs = std::vector<s7_int> (1, -1);
@@ -111,30 +113,57 @@ njson_error (s7_scheme* sc, const char* type_name, const std::string& msg, s7_po
 
 static s7_pointer
 make_njson_handle (s7_scheme* sc, s7_int id) {
-  return s7_cons (sc, s7_make_symbol (sc, NJSON_HANDLE_TAG), s7_make_integer (sc, id));
+  s7_int generation = 0;
+  if (id > 0) {
+    size_t index = static_cast<size_t> (id);
+    if (index < njson_handle_generations.size ()) {
+      generation = njson_handle_generations[index];
+    }
+  }
+  return s7_cons (
+    sc, s7_make_symbol (sc, NJSON_HANDLE_TAG), s7_cons (sc, s7_make_integer (sc, id), s7_make_integer (sc, generation)));
 }
 
 static bool
-is_njson_handle (s7_pointer x) {
+is_njson_handle (s7_pointer x, s7_int* id_out = nullptr, s7_int* generation_out = nullptr) {
   if (!s7_is_pair (x)) return false;
   s7_pointer tag = s7_car (x);
-  s7_pointer id  = s7_cdr (x);
+  s7_pointer payload = s7_cdr (x);
   if (!s7_is_symbol (tag)) return false;
   if (strcmp (s7_symbol_name (tag), NJSON_HANDLE_TAG) != 0) return false;
-  return s7_is_integer (id);
+  if (!s7_is_pair (payload)) return false;
+  s7_pointer id = s7_car (payload);
+  s7_pointer generation = s7_cdr (payload);
+  if (!s7_is_integer (id) || !s7_is_integer (generation)) return false;
+  if (id_out) *id_out = s7_integer (id);
+  if (generation_out) *generation_out = s7_integer (generation);
+  return true;
 }
 
 static bool
 extract_njson_handle_id (s7_scheme* sc, s7_pointer handle, s7_int& id, std::string& error_msg) {
-  if (!is_njson_handle (handle)) {
+  s7_int generation = 0;
+  if (!is_njson_handle (handle, &id, &generation)) {
     error_msg = "expected njson handle";
     return false;
   }
-  id = s7_integer (s7_cdr (handle));
   if (id <= 0) {
     error_msg = "invalid njson handle id";
     return false;
   }
+  if (generation <= 0) {
+    error_msg = "invalid njson handle generation";
+    return false;
+  }
+  size_t index = static_cast<size_t> (id);
+  if (index >= njson_handle_generations.size ()) {
+    error_msg = "njson handle does not exist (may have been freed)";
+    return false;
+  }
+  if (njson_handle_generations[index] != generation) {
+    error_msg = "njson handle generation mismatch (stale handle)";
+    return false;
+  }
   if (static_cast<size_t> (id) >= njson_handle_store.size () || !njson_handle_store[static_cast<size_t> (id)]) {
     error_msg = "njson handle does not exist (may have been freed)";
     return false;
@@ -167,6 +196,13 @@ njson_ensure_keys_cache_size (size_t n) {
   }
 }
 
+static void
+njson_ensure_generations_size (size_t n) {
+  if (njson_handle_generations.size () < n) {
+    njson_handle_generations.resize (n, 0);
+  }
+}
+
 static void
 njson_clear_keys_cache_slot (s7_scheme* sc, s7_int id) {
   if (id <= 0) return;
@@ -230,12 +266,23 @@ store_njson_value (json&& value) {
   if (!njson_handle_free_ids.empty ()) {
     s7_int id = njson_handle_free_ids.back ();
     njson_handle_free_ids.pop_back ();
-    njson_handle_store[static_cast<size_t> (id)] = std::make_unique<json> (std::move (value));
+    size_t index = static_cast<size_t> (id);
+    njson_ensure_generations_size (index + 1);
+    s7_int generation = njson_handle_generations[index];
+    if (generation <= 0 || generation == (std::numeric_limits<s7_int>::max) ()) {
+      generation = 1;
+    }
+    else {
+      generation += 1;
+    }
+    njson_handle_generations[index] = generation;
+    njson_handle_store[index] = std::make_unique<json> (std::move (value));
     njson_ensure_keys_cache_size (njson_handle_store.size ());
     return id;
   }
 
   njson_handle_store.push_back (std::make_unique<json> (std::move (value)));
+  njson_handle_generations.push_back (1);
   njson_ensure_keys_cache_size (njson_handle_store.size ());
   s7_int id = static_cast<s7_int> (njson_handle_store.size () - 1);
   return id;
@@ -381,10 +428,19 @@ scheme_to_njson_scalar_or_handle (s7_scheme* sc, s7_pointer value, json& out, st
     out = static_cast<long long> (s7_integer (value));
     return true;
   }
-  if (s7_is_real (value) || s7_is_number (value)) {
-    out = s7_number_to_real (sc, value);
+  if (s7_is_real (value)) {
+    double real_value = s7_number_to_real (sc, value);
+    if (!std::isfinite (real_value)) {
+      error_msg = "number must be finite (NaN/Inf are not valid JSON numbers)";
+      return false;
+    }
+    out = real_value;
     return true;
   }
+  if (s7_is_number (value)) {
+    error_msg = "number must be real and finite";
+    return false;
+  }
   if (s7_is_symbol (value)) {
     const char* symbol_name = s7_symbol_name (value);
     if (strcmp (symbol_name, "null") == 0) {
@@ -795,6 +851,9 @@ njson_apply_update_on_root (s7_scheme* sc, json& root, const std::vector<s7_poin
     return njson_error (sc, "key-error", std::string (api_name) + ": path not found: cannot drop from non-container value",
                         last_key);
   }
+  if (op == njson_update_op::set) {
+    return njson_error (sc, "key-error", std::string (api_name) + ": set target must be array or object", last_key);
+  }
   return nullptr;
 }
 
diff --git a/tests/goldfish/liii/njson-test.scm b/tests/goldfish/liii/njson-test.scm
index 74f08878..ffa153fa 100644
--- a/tests/goldfish/liii/njson-test.scm
+++ b/tests/goldfish/liii/njson-test.scm
@@ -42,6 +42,15 @@
             (car payload)
             "")))))
 
+(define (capture-type-error-message thunk)
+  (catch 'type-error
+    thunk
+    (lambda args
+      (let ((payload (if (and (pair? args) (pair? (cdr args))) (cadr args) '())))
+        (if (and (pair? payload) (string? (car payload)))
+            (car payload)
+            "")))))
+
 #|
 let-njson
 统一处理“可能是 njson 句柄，也可能是普通标量”的作用域宏。
@@ -221,6 +230,26 @@ json-string : string
 (check-catch 'type-error (njson-ref njson-string-free-check "x"))
 (check-catch 'type-error (njson-free 'foo))
 
+(define stale-handle-old (string->njson "{\"a\":1}"))
+(check (njson-ref stale-handle-old "a") => 1)
+(check-true (njson-free stale-handle-old))
+(let-njson ((stale-handle-new (string->njson "{\"b\":2}")))
+  (check (njson-ref stale-handle-new "b") => 2)
+  (check-catch 'type-error (njson-ref stale-handle-old "b"))
+  (check-catch 'type-error (njson-free stale-handle-old))
+  ;; stale free must not affect the new handle if id is reused.
+  (check (njson-ref stale-handle-new "b") => 2))
+
+;; Old forged shape `(njson-handle . id)` must be rejected.
+(check-catch 'type-error (njson-ref (cons 'njson-handle 1) "x"))
+;; Forged generation must be rejected.
+(let-njson ((root (string->njson "{\"secret\":42}")))
+  (let* ((payload (cdr root))
+         (id (car payload))
+         (gen (cdr payload))
+         (forged (cons 'njson-handle (cons id (+ gen 1)))))
+    (check-catch 'type-error (njson-ref forged "secret"))))
+
 #|
 njson?
 判断值是否为 njson-handle。
@@ -236,7 +265,7 @@ x : any
 
 行为逻辑
 --------
-1. 仅检查结构是否符合 njson 句柄格式（`(njson-handle . id)`）。
+1. 仅检查结构是否符合 njson 句柄格式（`(njson-handle . (id . generation))`）。
 2. 不负责判断该句柄是否已释放；“已释放”通常在具体 API 调用时触发错误。
 
 返回值
@@ -430,6 +459,12 @@ value : njson-handle | string | number | boolean | 'null
 (check-catch 'type-error (njson-set 'foo "meta" "os" "debian"))
 (let-njson ((root (string->njson sample-json)))
   (check-catch 'key-error (njson-set root 'meta "os" "debian")))
+(let-njson ((root (string->njson sample-json)))
+  (check-catch 'type-error (njson-set root "score" +nan.0))
+  (check-catch 'type-error (njson-set root "score" +inf.0))
+  (check-catch 'type-error (njson-set root "score" -inf.0))
+  (check (capture-type-error-message (lambda () (njson-set root "score" +nan.0)))
+         => "g_njson-set: number must be finite (NaN/Inf are not valid JSON numbers)"))
 (let-njson ((root (string->njson sample-json)))
   (check-catch 'key-error (njson-set root "nums" 5 1)))
 (let-njson ((root (string->njson sample-json)))
@@ -441,6 +476,14 @@ value : njson-handle | string | number | boolean | 'null
 (let-njson ((root (string->njson sample-json)))
   (check (capture-key-error-message (lambda () (njson-set root "nums" 5 1)))
          => "g_njson-set: array index out of range (index=5, size=5)"))
+(let-njson ((root (string->njson "1")))
+  (check-catch 'key-error (njson-set root "x" 1))
+  (check (capture-key-error-message (lambda () (njson-set root "x" 1)))
+         => "g_njson-set: set target must be array or object"))
+(let-njson ((root (string->njson sample-json)))
+  (check-catch 'key-error (njson-set root "name" "x" "y"))
+  (check (capture-key-error-message (lambda () (njson-set root "name" "x" "y")))
+         => "g_njson-set: set target must be array or object"))
 
 #|
 njson-set!
@@ -494,6 +537,12 @@ value : njson-handle | string | number | boolean | 'null
 (check-catch 'type-error (njson-set! 'foo "meta" "os" "debian"))
 (let-njson ((root (string->njson sample-json)))
   (check-catch 'key-error (njson-set! root 'meta "os" "debian")))
+(let-njson ((root (string->njson sample-json)))
+  (check-catch 'type-error (njson-set! root "score" +nan.0))
+  (check-catch 'type-error (njson-set! root "score" +inf.0))
+  (check-catch 'type-error (njson-set! root "score" -inf.0))
+  (check (capture-type-error-message (lambda () (njson-set! root "score" +nan.0)))
+         => "g_njson-set!: number must be finite (NaN/Inf are not valid JSON numbers)"))
 (let-njson ((root (string->njson sample-json)))
   (check-catch 'key-error (njson-set! root "nums" 5 1)))
 (let-njson ((root (string->njson sample-json)))
@@ -502,6 +551,14 @@ value : njson-handle | string | number | boolean | 'null
          => "g_njson-set!: path not found: missing object key 'missing'"))
 (let-njson ((root (string->njson sample-json)))
   (check-catch 'key-error (njson-set! root "nums" 999 1)))
+(let-njson ((root (string->njson "1")))
+  (check-catch 'key-error (njson-set! root "x" 1))
+  (check (capture-key-error-message (lambda () (njson-set! root "x" 1)))
+         => "g_njson-set!: set target must be array or object"))
+(let-njson ((root (string->njson sample-json)))
+  (check-catch 'key-error (njson-set! root "name" "x" "y"))
+  (check (capture-key-error-message (lambda () (njson-set! root "name" "x" "y")))
+         => "g_njson-set!: set target must be array or object"))
 
 #|
 njson-append
@@ -550,6 +607,11 @@ value : njson-handle | string | number | boolean | 'null
 
 (check-catch 'type-error (njson-append 'foo 1))
 (let-njson ((root (string->njson sample-json)))
+  (check-catch 'type-error (njson-append root "nums" +nan.0))
+  (check-catch 'type-error (njson-append root "nums" +inf.0))
+  (check-catch 'type-error (njson-append root "nums" -inf.0))
+  (check (capture-type-error-message (lambda () (njson-append root "nums" +nan.0)))
+         => "g_njson-append: number must be finite (NaN/Inf are not valid JSON numbers)")
   (check-catch 'key-error (njson-append root))
   (check-catch 'key-error (njson-append root "as"))
   (check (capture-key-error-message (lambda () (njson-append root "as")))
@@ -606,6 +668,11 @@ value : njson-handle | string | number | boolean | 'null
 
 (check-catch 'type-error (njson-append! 'foo 1))
 (let-njson ((root (string->njson sample-json)))
+  (check-catch 'type-error (njson-append! root "nums" +nan.0))
+  (check-catch 'type-error (njson-append! root "nums" +inf.0))
+  (check-catch 'type-error (njson-append! root "nums" -inf.0))
+  (check (capture-type-error-message (lambda () (njson-append! root "nums" +nan.0)))
+         => "g_njson-append!: number must be finite (NaN/Inf are not valid JSON numbers)")
   (check-catch 'key-error (njson-append! root))
   (check-catch 'key-error (njson-append! root "as"))
   (check (capture-key-error-message (lambda () (njson-append! root "as")))
@@ -1006,6 +1073,14 @@ value : njson-handle | string | number | boolean | 'null
 (check (njson->string #f) => "false")
 (let-njson ((root (string->njson "{\"b\":1,\"a\":2}")))
   (check (njson->string root) => "{\"a\":2,\"b\":1}"))
+(check-catch 'type-error (njson->string +nan.0))
+(check-catch 'type-error (njson->string +inf.0))
+(check-catch 'type-error (njson->string -inf.0))
+(check-catch 'type-error (njson->string 1+2i))
+(check (capture-type-error-message (lambda () (njson->string +nan.0)))
+       => "g_njson-json->string: number must be finite (NaN/Inf are not valid JSON numbers)")
+(check (capture-type-error-message (lambda () (njson->string 1+2i)))
+       => "g_njson-json->string: number must be real and finite")
 (check-catch 'type-error (njson->string 'foo))
 
 (define njson-string-freed (string->njson "{\"k\":1}"))