Buffer Overflow vulnerability in Avast AntiVirus before v.19.7 allows a local attacker to cause a denial of service via a crafted request to the aswSnx.sys driver.

A sym-linked file accessed via the repair function in Avast Antivirus <24.2 on Windows may allow user to elevate privilege to delete arbitrary files or run processes as NT AUTHORITY\SYSTEM. The vulnerability exists within the "Repair" (settings -> troubleshooting -> repair) feature, which attempts to delete a file in the current user's AppData directory as NT AUTHORITY\SYSTEM. A low-privileged user can make a pseudo-symlink and a junction folder and point to a file on the system. This can provide a low-privileged user an Elevation of Privilege to win a race-condition which will re-create the system files and make Windows callback to a specially-crafted file which could be used to launch a privileged shell instance.

This issue affects Avast Antivirus prior to 24.2.

Integer Overflow or Wraparound vulnerability in Avast Antivirus (25.1.981.6) on Windows allows Privilege Escalation.This issue affects Antivirus: from 25.1.981.6 before 25.3.

Double fetch in sandbox kernel driver in Avast/AVG Antivirus <25.3  on windows allows local attacker to escalate privelages via pool overflow.

This vulnerability allows local attackers to escalate privileges on affected installations of Avast Free Antivirus. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The ZDI has assigned a CVSS rating of 8.8. The following CVEs are assigned: CVE-2025-3500.

This vulnerability allows local attackers to escalate privileges on affected installations of Avast Free Antivirus. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The ZDI has assigned a CVSS rating of 8.8. The following CVEs are assigned: CVE-2025-3500.

A vulnerability within the malware removal functionality of Avast and AVG Antivirus allowed an attacker with write access to the filesystem, to escalate his privileges in certain scenarios. The issue was fixed with Avast and AVG Antivirus version 22.10.

Norton, Avira, Avast and AVG Antivirus for Windows may be susceptible to a Privilege Escalation vulnerability, which is a type of issue whereby an attacker may attempt to compromise the software application to gain elevated access to resources that are normally protected from an application or user.

Avast and AVG Antivirus for Windows were susceptible to a Time-of-check/Time-of-use (TOCTOU) vulnerability in the restore process leading to arbitrary file creation. The issue was fixed with Avast and AVG Antivirus version 22.11

Avast and AVG Antivirus for Windows were susceptible to a NULL pointer dereference issue via RPC-interface. The issue was fixed with Avast and AVG Antivirus version 22.11

Avast and AVG Antivirus for Windows were susceptible to a Time-of-check/Time-of-use (TOCTOU) vulnerability in the Quarantine process, leading to arbitrary file/directory deletion. The issue was fixed with Avast and AVG Antivirus version 22.11 and virus definitions from 14 February 2023 or later.

Avast Free Antivirus AvastSvc Link Following Local Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Avast Free Antivirus. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the Avast Service. By creating a symbolic link, an attacker can abuse the service to delete a folder. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-23731.

Avast Free Antivirus AvastSvc Link Following Local Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Avast Free Antivirus. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the Avast Service. By creating a symbolic link, an attacker can abuse the service to delete a folder. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-22963.

Avast Free Antivirus AvastSvc Link Following Local Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Avast Free Antivirus. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the Avast Service. By creating a symbolic link, an attacker can abuse the service to delete a file. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-22272.

Avast Free Antivirus Link Following Denial-of-Service Vulnerability. This vulnerability allows local attackers to create a denial-of-service condition on affected installations of Avast Free Antivirus. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the Avast Service. By creating a symbolic link, an attacker can abuse the service to create a folder. An attacker can leverage this vulnerability to create a denial-of-service condition on the system. Was ZDI-CAN-22806.

A time-of-check to time-of-use (TOCTOU) bug in handling of IOCTL (input/output control) requests. This TOCTOU bug leads to an out-of-bounds write vulnerability which can be further exploited, allowing an attacker to gain full local privilege escalation on the system.This issue affects Avast/Avg Antivirus: 23.8.

Sandbox component in Avast Antivirus prior to 20.4 has an insecure permission which could be abused by local user to control the outcome of scans, and therefore evade detection or delete arbitrary system files.

Multiple privilege escalation vulnerabilities in Avast Antivirus prior to 20.4 allow a local user to gain elevated privileges by calling unnecessarily powerful internal methods of the main antivirus service which could lead to the (1) arbitrary file delete, (2) write and (3) reset security.

Privilege escalation vulnerability in the Sandbox component of Avast Antivirus prior to 20.4 allows a local sandboxed code to gain elevated privileges by using system IPC interfaces which could lead to exit the sandbox and acquire SYSTEM privileges.

Privilege escalation vulnerability in Avast Antivirus prior to 20.4 allows a local user to gain elevated privileges by "hollowing" trusted process which could lead to the bypassing of Avast self-defense.

Privilege escalation vulnerability in the Self-Defense driver of Avast Antivirus prior to 20.8 allows a local user with SYSTEM privileges to gain elevated privileges by "hollowing" process wscproxy.exe which could lead to acquire antimalware (AM-PPL) protection.

The AVGUI.exe of AVG/Avast Antivirus before versions before 24.1 can allow a local attacker to escalate privileges via an COM hijack in a time-of-check to time-of-use (TOCTOU) when self protection is disabled.

Avast allows remote attackers to cause a denial of service (memory corruption) and possibly execute arbitrary code via a crafted PE file, related to authenticode parsing.

Multiple stack-based buffer overflows in avast! Linux Home Edition 1.0.5, 1.0.5-1, and 1.0.8 allow remote attackers to cause a denial of service (application crash) or execute arbitrary code via a malformed (1) ISO or (2) RPM file.

aavmker4.sys in avast! Home and Professional 4.7 for Windows does not properly validate input to IOCTL 0xb2d60030, which allows local users to gain privileges via certain IOCTL requests.

Heap-based buffer overflow in aswRdr.sys (aka the TDI RDR driver) in avast! Home and Professional 4.8.1356.0 allows local users to cause a denial of service (memory corruption) or possibly gain privileges via crafted arguments to IOCTL 0x80002024.

Stack-based buffer overflow in aswMon2.sys in avast! Home and Professional for Windows 4.8.1351, and possibly other versions before 4.8.1356, allows local users to cause a denial of service (system crash) and possibly gain privileges via a crafted IOCTL request to IOCTL 0xb2c80018.

Unspecified vulnerability in ashWsFtr.dll in avast! Home and Professional for Windows before 4.8.1356 has unknown impact and local attack vectors.

aavmKer4.sys in avast! Home and Professional for Windows before 4.8.1356 does not properly validate input to IOCTLs (1) 0xb2d6000c and (2) 0xb2d60034, which allows local users to gain privileges via IOCTL requests using crafted kernel addresses that trigger memory corruption, a different vulnerability than CVE-2008-1625.

Heap-based buffer overflow in the Avast virtualization driver (aswSnx.sys) in Avast Internet Security, Pro Antivirus, Premier, and Free Antivirus before 11.1.2253 allows local users to gain privileges via a Unicode file path in an IOCTL request.