Mike Zhang

A flaw exists in Avast Antivirus on MacOS that involves a heap-based buffer overflow and out-of-bounds write condition. Processing a specially crafted Mach-O file could lead to local code execution or a denial of service, impacting the antivirus protection.

A NULL pointer dereference issue exists in Avast Antivirus when scanning a malformed Windows PE file. This can cause the antivirus process to crash on MacOS and Linux systems.

A heap-based buffer overflow and out-of-bounds read issue exists in Avast Antivirus on MacOS when scanning a malformed file. This can lead to local execution of code or a denial-of-service of the antivirus engine process. The issue is triggered when processing a specially crafted file. The vulnerability affects the antivirus engine.

This issue was addressed with improved checks. Processing a maliciously crafted image may lead to arbitrary code execution.

The issue arises in the `SplashOutputDev::endType3Char(GfxState *state)` function, where it attempts to use the freed `t3GlyphStack->cache`, resulting in a heap-use-after-free problem. This occurs because the previous fix for nested Type 3 characters did not correctly handle cases where a Type 3 character refers to another character in the same Type 3 font.

The issue is related to multiple memory corruption problems that have been addressed with improved memory handling. Processing maliciously crafted web content may lead to arbitrary code execution.

A stack-based buffer over-read issue exists in the FoFiTrueType::dumpString function. This can be triggered by sending crafted TrueType data in a PDF document to the pdftops tool, potentially allowing an attacker to cause Denial of Service or leak memory data into dump content.

The issue is caused by a buffer overflow in memory, which may lead to arbitrary code execution when processing maliciously crafted web content. This can allow a remote attacker to execute arbitrary code using a specially crafted website.