CVE-2026-6676 PUBLISHED

Avira antivirus engine heap buffer OOB write when scanning a malformed POSIX tar archive

Assigner: GEN
Reserved: 20.04.2026 Published: 12.06.2026 Updated: 12.06.2026

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.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS Score: 7.8

Attack Vector	Local	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	High
User Interaction	Required	Availability Impact	High

CVSS 3.1

Product Status

Vendor	Gen Digital
Product	Avira Antivirus
Versions	Default: affected affected from 0 to 8.3.27.12 (excl.)

Solutions

Upgrade to Avira scan engine build 8.3.27.12 or any later engine release. Builds at or above 8.3.27.12 include the fix.

Credits

Mike Zhang, an independent security researcher reporter

References

https://www.gendigital.com/us/en/contact-us/security-advisories/

Problem Types

CWE-787 Out-of-bounds Write CWE

Impacts

CAPEC-549 Local Execution of Code