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Fixed nullptr crash in ETH IP comparing code #5796

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Fixed nullptr crash in ETH IP comparing code #5796

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2 changes: 1 addition & 1 deletion wled00/network.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -295,7 +295,7 @@ bool initEthernet()
}

// https://github.com/wled/WLED/issues/5247
if (multiWiFi[0].staticIP != (uint32_t)0x00000000 && multiWiFi[0].staticGW != (uint32_t)0x00000000) {
if (multiWiFi.size() && multiWiFi[0].staticIP != IPAddress() && multiWiFi[0].staticGW != IPAddress()) {

@softhack007 softhack007 Aug 10, 2026

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It might be that the addition of if (multiWiFi.size() is the actual fix.

@coderabbitai how is IPAddress() defined? Is it the same as 0.0.0.0 ?

@coderabbitai coderabbitai Bot Aug 10, 2026

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🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
set -euo pipefail

printf '%s\n' '=== IPAddress declarations/uses ==='
rg -n -C 3 'class IPAddress|IPAddress::IPAddress|IPAddress\(\)' \
  -g '*.{h,hpp,cpp,ino}' .

printf '%s\n' '=== Arduino-ESP32 framework version references ==='
rg -n -C 2 'arduino-esp32|ESP_ARDUINO_VERSION|platform.*espressif32' \
  -g 'platformio.ini' -g 'platformio*.ini' -g 'package.json' -g '*.json' -g '*.md' .

Length of output: 14902

@softhack007, yes. In Arduino-ESP32, a default-constructed IPAddress() has all four IPv4 octets set to zero. It represents 0.0.0.0.

The two changes address different conditions:

  • multiWiFi.size() prevents access to multiWiFi[0] when the vector is empty. This can be the crash fix if no Wi-Fi entry exists.
  • staticIP != IPAddress() and staticGW != IPAddress() compare two IPAddress objects. This selects the IPAddress comparison overload.

The old (uint32_t)0x00000000 value can convert to a null pointer. It then selects the const uint8_t * comparison overload shown in the Comment image. That overload reads the pointer as address bytes, so it can dereference nullptr.

Therefore, IPAddress() is the correct explicit test for 0.0.0.0, and multiWiFi.size() is the required bounds guard. Both changes are valid.
🐇🔍

You are interacting with an AI system.

ETH.config(multiWiFi[0].staticIP, multiWiFi[0].staticGW, multiWiFi[0].staticSN, dnsAddress);
} else {
ETH.config(INADDR_NONE, INADDR_NONE, INADDR_NONE);
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