diff --git a/src/sql/postgres/protocol/ErrorResponse.zig b/src/sql/postgres/protocol/ErrorResponse.zig
index ee2d5b7ee4..64d13549bf 100644
--- a/src/sql/postgres/protocol/ErrorResponse.zig
+++ b/src/sql/postgres/protocol/ErrorResponse.zig
@@ -132,7 +132,9 @@ pub fn toJS(this: ErrorResponse, globalObject: *jsc.JSGlobalObject) JSValue {
     const line_slice = if (line.isEmpty()) null else line.byteSlice();
     const routine_slice = if (routine.isEmpty()) null else routine.byteSlice();
 
-    return createPostgresError(globalObject, b.allocatedSlice()[0..b.len], .{
+    const error_message = if (b.len > 0) b.allocatedSlice()[0..b.len] else "";
+
+    return createPostgresError(globalObject, error_message, .{
         .code = error_code,
         .errno = errno,
         .detail = detail_slice,
diff --git a/test/regression/issue/postgres-stringbuilder-assertion-aggressive.test.ts b/test/regression/issue/postgres-stringbuilder-assertion-aggressive.test.ts
new file mode 100644
index 0000000000..991d85447d
--- /dev/null
+++ b/test/regression/issue/postgres-stringbuilder-assertion-aggressive.test.ts
@@ -0,0 +1,46 @@
+import { SQL } from "bun";
+import { expect, test } from "bun:test";
+import net from "net";
+
+test("PostgreSQL StringBuilder assertion - aggressive empty error test", async () => {
+  const server = net.createServer(socket => {
+    // Immediately send an error response with completely empty fields
+    // This is more likely to trigger the assertion
+    socket.write(createPostgresPacket("E", Buffer.from("\0"))); // Terminator only
+    socket.destroy();
+  });
+
+  await new Promise<void>(r => server.listen(0, "127.0.0.1", () => r()));
+  const port = (server.address() as net.AddressInfo).port;
+
+  const sql = new SQL({
+    url: `postgres://test@127.0.0.1:${port}/test`,
+    max: 10,
+    connection_timeout: 0.1,
+  });
+
+  const promises = [];
+  for (let i = 0; i < 20; i++) {
+    promises.push(
+      sql`SELECT ${i}`.catch(err => {
+        // We expect errors, just checking for crashes
+        return null;
+      }),
+    );
+  }
+
+  await Promise.all(promises);
+  await sql.close();
+  server.close();
+
+  // If we get here without crashing, the test passes
+  expect(true).toBe(true);
+});
+
+function createPostgresPacket(type: string, data: Buffer): Buffer {
+  const len = data.length + 4;
+  const header = Buffer.alloc(5);
+  header.write(type, 0);
+  header.writeInt32BE(len, 1);
+  return Buffer.concat([header, data]);
+}