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Heap buffer out-of-bounds write vulnerability in Avira...

High severity Unreviewed Published Jun 13, 2026 to the GitHub Advisory Database • Updated Jun 13, 2026

Package

No package listed— Suggest a package

Affected versions

Unknown

Patched versions

Unknown

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.

References

Published by the National Vulnerability Database Jun 12, 2026
Published to the GitHub Advisory Database Jun 13, 2026
Last updated Jun 13, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS score

Weaknesses

Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer. Learn more on MITRE.

CVE ID

CVE-2026-6676

GHSA ID

GHSA-c89p-wq36-89h3

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

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