CVE-2024-48985: arm mbed Classic Buffer Overflow

Vulnerability summary

CVE-2024-48985 is a high (CVSS 7.5) Classic Buffer Overflow vulnerability in arm mbed. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.2% of scored vulnerabilities.

Timeline

1. 20-11-2024
   PublishedVulnerability first disclosed.
2. 25-11-2024
   Last modifiedVulnerability information updated.

Description

An issue was discovered in MBed OS 6.16.0. During processing of HCI packets, the software dynamically determines the length of the packet data by reading 2 bytes from the packet data. A buffer is then allocated to contain the entire packet, the size of which is calculated as the length of the packet body determined earlier and the header length. If the allocate fails because the specified packet is too large, no exception handling occurs and hciTrSerialRxIncoming continues to write bytes into the 4-byte large temporary header buffer, leading to a buffer overflow. This can be leveraged into an arbitrary write by an attacker. It is possible to overwrite the pointer to the buffer that is supposed to receive the contents of the packet body but which couldn't be allocated. One can then overwrite the state variable used by the function to determine which step of the parsing process is currently being executed. This advances the function to the next state, where it proceeds to copy data to that arbitrary location. The packet body is then written wherever the corrupted data pointer is pointing.

• CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.