libde265, an open source H.265 video codec implementation, has a heap-based buffer overflow vulnerability (CWE-122) in versions before 1.1.1. The flaw arises from using signed 32-bit arithmetic to compute the sample adaptive offset input-buffer size, which can be manipulated by a crafted HEVC stream with large dimensions and 16-bit luma samples. This leads to an integer overflow (CWE-190), resulting in an undersized memory allocation and an out-of-bounds heap read. The vulnerability may cause heap data exposure in the decoded output or cause the decoder to crash. The vulnerability is addressed in libde265 version 1.1.1.

An attacker can craft a malicious HEVC video stream that triggers an integer overflow and heap-based buffer overflow in libde265 versions prior to 1.1.1. This can lead to exposure of heap memory contents in the decoded output or cause the decoder to crash, resulting in denial of service. There is no indication of code execution or privilege escalation from the provided data.

Upgrade libde265 to version 1.1.1 or later, which contains the official patch addressing this vulnerability. No other mitigations are indicated or required.