CVE-2024-42040

What it actually does

Buffer overflow in net/bootp.c allows crafted DHCP responses on the local network to leak 4-32 bytes of adjacent memory containing DHCP-provided parameters.

Why it matters to the business

Attackers on the same network can obtain limited sensitive data from affected devices, increasing risk of further targeted attacks; widespread use in embedded and Android environments raises exposure for many organizations.

How an attack unfolds

An attacker on the local network sends specially crafted DHCP responses that trigger the overflow in U-Boot's BOOTP handling, causing the device to transmit memory contents from beyond the packet buffer back over the network.

How to fix it

Upgrade affected Android Wifi modules to the fixed versions released 2022-09-01 for Android 13 and 13-next; apply vendor patches for any U-Boot-based firmware that incorporate the corrected net/bootp.c logic.

How to confirm the fix worked

Confirm the installed U-Boot or Android Wifi package version matches or exceeds the 2022-09-01 fixes; review boot logs and DHCP packet handling code for the corrected buffer bounds checks.

Typical attack path

1. Attacker gains access to the local network segment used for DHCP.
2. Attacker crafts and transmits malicious DHCP responses targeting the vulnerable BOOTP code path.
3. Device processes the response and leaks 4-32 bytes of adjacent memory over the network.
4. Attacker captures the leaked data for reconnaissance or credential harvesting.

How to detect it

Monitor DHCP traffic for anomalous response sizes or unexpected memory patterns; inspect device logs for unusual outbound packets following DHCP exchanges; review network captures for responses that exceed normal BOOTP packet lengths.

What your security team should do

• Prioritize patching all Android 13 and later devices to the September 2022 security level.
• Scan firmware images for vulnerable U-Boot versions and replace with patched builds.
• Segment networks to limit DHCP exposure for embedded devices until updates are applied.