CVE-2026-27750 Avira Internet Security Optimizer TOCTOU
A local attacker can exploit a TOCTOU race condition in Avira's Optimizer to delete protected system files, leading to privilege escalation or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-27750?
CVE-2026-27750 is a high-severity vulnerability in Gen Digital Inc. Avira Internet Security, published on 5 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Avira Internet Security contains a time-of-check time-of-use (TOCTOU) vulnerability in the Optimizer component. A privileged service running as SYSTEM identifies directories for cleanup during a scan phase and subsequently deletes them during a separate cleanup phase without revalidating the target path. A local attacker can replace a previously scanned directory with a junction or reparse point before deletion occurs, causing the privileged process to delete an unintended system location. This may result in deletion of protected files or directories and can lead to local privilege escalation, denial of service, or system integrity compromise depending on the affected target.
Weakness: CWE-367
Which versions are affected by CVE-2026-27750?
It affects 1 product.
Products include Avira Internet Security.
How do I fix CVE-2026-27750?
No fix has been published for CVE-2026-27750 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-27750 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27750 exists.
Other vulnerabilities in Gen Digital Inc. Avira Internet Security
Sources
Also known as GHSA-qfjh-mfrq-8j64.