CVE-2026-27750
TOCTOU Vulnerability in Avira Optimizer Enables Privilege Escalation
Publication date: 2026-03-05
Last updated on: 2026-04-01
Assigner: VulnCheck
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| avira | internet_security | to 1.1.114.3113 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-367 | The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-27750 is a time-of-check time-of-use (TOCTOU) race condition vulnerability found in the Optimizer component of Avira Internet Security.
A privileged service running with SYSTEM-level permissions first identifies directories for cleanup during a scan phase and later deletes them in a separate cleanup phase without revalidating the target paths.
A local attacker can exploit the time gap between these phases by replacing a previously scanned directory with a junction or reparse point before deletion occurs.
This causes the privileged process to delete unintended system locations, including protected files or directories.
How can this vulnerability impact me? :
The vulnerability can lead to deletion of protected files or directories by a privileged process.
This may result in local privilege escalation, denial of service, or compromise of system integrity depending on the affected target.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
[{'type': 'paragraph', 'content': "To mitigate the CVE-2026-27750 vulnerability, it is important to prevent exploitation of the TOCTOU race condition in Avira Internet Security's Optimizer component."}, {'type': 'list_item', 'content': 'Avoid running the vulnerable Avira Internet Security versions until a patch or update is applied.'}, {'type': 'list_item', 'content': 'Check for and apply any security updates or patches provided by Avira that address this vulnerability.'}, {'type': 'list_item', 'content': 'Limit local user permissions to reduce the risk of a local attacker exploiting the vulnerability.'}, {'type': 'list_item', 'content': 'Monitor system directories for suspicious junctions or reparse points that could be used to exploit the deletion process.'}] [1]