PatchSiren cyber security CVE debrief

CVE-2026-6676 Gen Digital CVE debrief

A heap buffer out-of-bounds write vulnerability exists in the Avira Antivirus engine when scanning a malformed POSIX tar archive. This issue, tracked as CVE-2026-6676, may allow for Local Execution of Code or Denial-of-Service of the antivirus engine process. The vulnerability affects Avira Antivirus on Windows, macOS, and Linux for engine builds before 8.3.27.12. The CVSS score for this vulnerability is 7.8, indicating a HIGH severity level.

Vendor: Gen Digital
Product: Avira Antivirus
CVSS: HIGH 7.8
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-06-12
Original CVE updated: 2026-06-12
Advisory published: 2026-06-12
Advisory updated: 2026-06-12

Who should care

Users of Avira Antivirus on Windows, macOS, and Linux with engine builds before 8.3.27.12 should be aware of this vulnerability and take necessary actions to mitigate the risk.

Technical summary

The vulnerability is caused by a heap buffer out-of-bounds write issue in the Avira Antivirus engine when processing a malformed POSIX tar archive. This could lead to Local Execution of Code or Denial-of-Service of the antivirus engine process.

Defensive priority

HIGH

Recommended defensive actions

Update Avira Antivirus engine to build 8.3.27.12 or later.
Ensure that all systems running Avira Antivirus are running the latest engine version.

Evidence notes

The CVE record and details were obtained from official sources.

Official resources

CVE-2026-6676 was published on 2026-06-12T23:16:45.007Z and has not been modified since then.