CVE-2019-18614: cypress cyw20735_firmware Out-of-bounds Write

Vulnerability summary

CVE-2019-18614 is a high (CVSS 7.8) Out-of-bounds Write vulnerability in cypress cyw20735_firmware. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 25.9% of scored vulnerabilities.

Timeline

1. 16-06-2020
   PublishedVulnerability first disclosed.
2. 05-08-2024
   Last modifiedVulnerability information updated.

Description

On the Cypress CYW20735 evaluation board, any data that exceeds 384 bytes is copied and causes an overflow. This is because the maximum BLOC buffer size for sending and receiving data is set to 384 bytes, but everything else is still configured to the usual size of 1092 (which was used for everything in the previous CYW20719 and later CYW20819 evaluation board). To trigger the overflow, an attacker can either send packets over the air or as unprivileged local user. Over the air, the minimal PoC is sending "l2ping -s 600" to the target address prior to any pairing. Locally, the buffer overflow is immediately triggered by opening an ACL or SCO connection to a headset. This occurs because, in WICED Studio 6.2 and 6.4, BT_ACL_HOST_TO_DEVICE_DEFAULT_SIZE and BT_ACL_DEVICE_TO_HOST_DEFAULT_SIZE are set to 384.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.