CVE-2017-18172

Vulnerability

In a device with a 1440x2560 screen, the check of contiguous buffer size during display operations in System UI overflows on certain buffer sizes, leading to an integer overflow or wraparound. This affects Qualcomm Snapdragon Automobile and Mobile platforms: MDM9635M, SD 400, SD 410/12, SD 425, SD 427, SD 430, SD 435, SD 450, SD 615/16/SD 415, SD 617, SD 625, SD 650/52, SD 800, SD 810, SD 820, SD 820A, SD 835, SDM630, SDM636, SDM660, and Snapdragon_High_Med_2016 [1].

Exploitation

An attacker requires local access to the device and the ability to trigger display operations that allocate a contiguous buffer of a size that causes the check to overflow. No authentication is needed beyond normal user-level access, as the vulnerable code is reachable from the System UI process [1]. The exploitation sequence involves sending malformed display commands or manipulating screen buffer allocations to cause the integer wraparound.

Impact

Successful exploitation can lead to denial of service via screen corruption or system instability, potentially allowing the attacker to cause the System UI to crash or behave unexpectedly. Information disclosure or elevation of privilege is not documented; the primary impact is on availability [1].

Mitigation

A fix was included in the Android Security Bulletin for July 2018, with security patch level 2018-07-05 or later [1]. Users should ensure their devices receive this update from their device manufacturer or carrier. No workaround is provided, and the vulnerability is not listed on CISA's Known Exploited Vulnerabilities (KEV) catalog. Affected devices that are no longer receiving security updates remain vulnerable.