Cyber Posture

CVE-2025-8351

Critical

Published: 01 December 2025

Published
01 December 2025
Modified
15 April 2026
KEV Added
Patch
CVSS Score 9.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.0006 17.0th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Description

Adversaries may disable, degrade, or tamper with security tools or applications (e.

Security Summary

CVE-2025-8351 is a heap-based buffer overflow and out-of-bounds read vulnerability (CWE-122, CWE-125) in Avast Antivirus on macOS. The issue arises when the software scans a malformed file, potentially leading to local code execution or denial-of-service of the antivirus engine process. It affects Avast Antivirus versions from 8.3.70.94 before 8.3.70.98 and was published on 2025-12-01T16:15:57.857 with a CVSS v3.1 base score of 9.0 (AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).

Attackers require no privileges or user interaction and can exploit the vulnerability over the network, though it demands high attack complexity. Successful exploitation grants high-impact confidentiality, integrity, and availability violations with a changed scope, enabling local code execution within the antivirus process or denial-of-service that disrupts the engine.

Gen Digital has published a security advisory with details on mitigation, available at https://www.gendigital.com/us/en/contact-us/security-advisories/. Users should update to Avast Antivirus version 8.3.70.98 or later to address the vulnerability.

Details

CWE(s)
CWE-122CWE-125

MITRE ATT&CK Enterprise Techniques

T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1685 Disable or Modify Tools Defense Impairment
Adversaries may disable, degrade, or tamper with security tools or applications (e.
Why these techniques?

Vulnerability enables remote heap buffer overflow in Avast Antivirus on macOS for local code execution or DoS on the AV engine process, directly facilitating Exploitation for Defense Evasion and Disable or Modify Tools.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

References