From c18fd9060bf62bf79baa4894adee2c69887c5b34 Mon Sep 17 00:00:00 2001
From: Nora Dossche <7771979+ndossche@users.noreply.github.com>
Date: Thu, 6 Aug 2026 05:18:25 +0200
Subject: [PATCH] sqlite: fix undefined behaviour in `Session::Changeset()`
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If `nChangeset == 0`, the pointer `pChangeset` may be nullptr.
Passing a nullptr to `memcpy()` is undefined behaviour.
This can be triggered by running the test suite under UBSAN.

Signed-off-by: ndossche <nora.dossche@ugent.be>
PR-URL: https://github.com/nodejs/node/pull/63637
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
---
 src/node_sqlite.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/node_sqlite.cc b/src/node_sqlite.cc
index 50bd3a36173..d474f89db90 100644
--- a/src/node_sqlite.cc
+++ b/src/node_sqlite.cc
@@ -3936,7 +3936,9 @@ void Session::Changeset(const FunctionCallbackInfo<Value>& args) {
   auto freeChangeset = OnScopeLeave([&] { sqlite3_free(pChangeset); });
 
   Local<ArrayBuffer> buffer = ArrayBuffer::New(env->isolate(), nChangeset);
-  std::memcpy(buffer->GetBackingStore()->Data(), pChangeset, nChangeset);
+  if (nChangeset > 0) {
+    std::memcpy(buffer->GetBackingStore()->Data(), pChangeset, nChangeset);
+  }
   Local<Uint8Array> uint8Array = Uint8Array::New(buffer, 0, nChangeset);
 
   args.GetReturnValue().Set(uint8Array);