ESP32 crashes and reboots when sending Zalgo Text

[TheStegosaurus1]

Im using a Basic Webserver like this:

#include <Arduino.h>
#include <WiFi.h>
#include <AsyncTCP.h>
#include <ESPAsyncWebServer.h>

AsyncWebServer server(80);

const char* ssid = "ssid";
const char* password = "********";

void setup() {

    Serial.begin(115200);
    WiFi.mode(WIFI_STA);
    WiFi.begin(ssid, password);
    if (WiFi.waitForConnectResult() != WL_CONNECTED) {
        Serial.printf("WiFi Failed!\n");
        return;
    }

    Serial.print("IP Address: ");
    Serial.println(WiFi.localIP());

    server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
        request->send(200, "text/plain", "Hello, world");
    });
    
    server.begin();
}

void loop() {
}

When I go to this URL which has some "cursed text" after the ?: zalgo_text.txt UTF-8 Encoded It crashes with this error:

Guru Meditation Error: Core  1 panic'ed (LoadProhibited). Exception was unhandled.      

Core  1 register dump:
PC      : 0x400894c7  PS      : 0x00060f30  A0      : 0x800e0117  A1      : 0x3ffda690  
A2      : 0x3ffda71c  A3      : 0x00000000  A4      : 0x00000001  A5      : 0x0000ff00  
A6      : 0x00ff0000  A7      : 0xff000000  A8      : 0x00000000  A9      : 0x00000000  
A10     : 0x00000001  A11     : 0x00000000  A12     : 0x00000000  A13     : 0x0000ff00  
A14     : 0x00ff0000  A15     : 0xff000000  SAR     : 0x00000015  EXCCAUSE: 0x0000001c
EXCVADDR: 0x00000000  LBEG    : 0x4008a691  LEND    : 0x4008a6a1  LCOUNT  : 0xffffffff  


Backtrace: 0x400894c4:0x3ffda690 0x400e0114:0x3ffda6b0 0x400e021e:0x3ffda6d0 0x400d63a1:0x3ffda6f0 0x400d67c1:0x3ffda760 0x400d6935:0x3ffda7b0 0x400d6b1d:0x3ffda800 0x40160b31:0x3ffda820 0x40160ba9:0x3ffda850 0x40161362:0x3ffda870

  #0  0x400894c4:0x3ffda690 in memmove at /builds/idf/crosstool-NG/.build/HOST-x86_64-w64-mingw32/xtensa-esp32-elf/src/newlib/newlib/libc/string/memmove.c:66
  #1  0x400e0114:0x3ffda6b0 in String::move(String&) at C:/Users/User/.platformio/packages/framework-arduinoespressif32/cores/esp32/WString.cpp:237
  #2  0x400e021e:0x3ffda6d0 in String::operator=(String&&) at C:/Users/User/.platformio/packages/framework-arduinoespressif32/cores/esp32/WString.cpp:277
  #3  0x400d63a1:0x3ffda6f0 in AsyncWebServerRequest::_parseReqHead() at .pio/libdeps/esp_wroom_02/ESP Async WebServer/src/WebRequest.cpp:280 (discriminator 1)
  #4  0x400d67c1:0x3ffda760 in AsyncWebServerRequest::_parseLine() at .pio/libdeps/esp_wroom_02/ESP Async WebServer/src/WebRequest.cpp:561
  #5  0x400d6935:0x3ffda7b0 in AsyncWebServerRequest::_onData(void*, unsigned int) at .pio/libdeps/esp_wroom_02/ESP Async WebServer/src/WebRequest.cpp:123
  #6  0x400d6b1d:0x3ffda800 in std::_Function_handler<void (void*, AsyncClient*, void*, unsigned int), AsyncWebServerRequest::AsyncWebServerRequest(AsyncWebServer*, AsyncClient*)::{lambda(void*, AsyncClient*, void*, unsigned int)#8}>::_M_invoke(std::_Any_data const&, void*&&, AsyncClient*&&, std::_Any_data const&, unsigned int&&) at .pio/libdeps/esp_wroom_02/ESP Async WebServer/src/WebRequest.cpp:76
      (inlined by) _M_invoke at c:\users\user\.platformio\packages\toolchain-xtensa-esp32\xtensa-esp32-elf\include\c++\8.4.0\bits/std_function.h:297
  #7  0x40160b31:0x3ffda820 in std::function<void (void*, AsyncClient*, void*, unsigned int)>::operator()(void*, AsyncClient*, void*, unsigned int) const at c:\users\user\.platformio\packages\toolchain-xtensa-esp32\xtensa-esp32-elf\include\c++\8.4.0\bits/std_function.h:687
      (inlined by) AsyncClient::_recv(tcp_pcb*, pbuf*, signed char) at .pio/libdeps/esp_wroom_02/AsyncTCP/src/AsyncTCP.cpp:915
  #8  0x40160ba9:0x3ffda850 in AsyncClient::_s_recv(void*, tcp_pcb*, pbuf*, signed char) at .pio/libdeps/esp_wroom_02/AsyncTCP/src/AsyncTCP.cpp:1191
  #9  0x40161362:0x3ffda870 in _async_service_task(void*) at .pio/libdeps/esp_wroom_02/AsyncTCP/src/AsyncTCP.cpp:159
      (inlined by) _async_service_task at .pio/libdeps/esp_wroom_02/AsyncTCP/src/AsyncTCP.cpp:194




ELF file SHA256: 219f7cef713eeb1c

Rebooting...

According to the backtrace, this happens in WebRequest.cpp at line 280 g = u.substring(index +1);

[TheStegosaurus1]

For now i fixed it with a bit of a hacky solution by only processing a requests parameters if its shorter than 1024 Characters. WebRequest.cpp:278

String g = String();
index = u.indexOf('?');
if(index > 0 && u.length() < 1024){
  g = u.substring(index +1);
  u = u.substring(0, index);
}
_url = urlDecode(u);
_addGetParams(g);