CVE-2026-6676

Deferred Deferred - Pending Action

Heap Buffer Overflow in Avira Antivirus Engine

Publication date: 2026-06-12

Last updated on: 2026-06-15

Assigner: NortonLifeLock Inc.

Description

Heap buffer out-of-bounds write vulnerability in Avira Antivirus engine when scanning a malformed POSIX tar archive may allow Local Execution of Code or Denial-of-Service of the antivirus engine process. This issue affects Avira Antivirus on Windows, macOS, and Linux for engine builds before 8.3.27.12.

CVSS Scores

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Meta Information

Published

2026-06-12

Last Modified

2026-06-15

Generated

2026-07-03

AI Q&A

2026-06-13

EPSS Evaluated

2026-07-02

NVD

CVE-2026-6676

EUVD

EUVD-2026-36631

Affected Vendors & Products

Vendor	Product	Version / Range
avira	antivirus	to 8.3.27.12 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-787	The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

Executive Summary

This vulnerability is a heap buffer out-of-bounds write in the Avira Antivirus engine that occurs when scanning a malformed POSIX tar archive.

It may allow a local attacker to execute code or cause a denial-of-service (DoS) by crashing the antivirus engine process.

Impact Analysis

The vulnerability can impact you by allowing local attackers to execute arbitrary code on your system or cause the antivirus engine to crash, resulting in denial-of-service.

This could compromise the security of your system or disrupt antivirus protection.

Mitigation Strategies

To mitigate this vulnerability, update the Avira Antivirus engine to version 8.3.27.12 or later on all affected platforms including Windows, macOS, and Linux.

Avoid scanning malformed POSIX tar archives until the update is applied to prevent potential local code execution or denial-of-service.

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