ESET Customer Advisory 2026-0005

March 23, 2026

Severity: Medium

Summary

ESET has taken action to resolve an issue with the epfwwfp driver through the release of an automatic product update to multiple ESET security solutions. These updates will be distributed to all affected applications, regardless of auto-update settings, as per the terms set in the EULA.

Details

A high-severity issue in the epfwwfp driver, utilized for network traffic scanning, has been identified during the investigation of support tickets reported by several customers.

The issue may manifest when an affected ESET security application is upgraded using a full installer, for instance, the .msi type (used, for example, in the Software Install tasks via ESET PROTECT). This could prevent the ESET service from stopping gracefully and in a timely manner, causing the upgrade to fail, leaving the system unprotected. As this is not acceptable, ESET decided to release a mandatory Auto-update to ensure continual protection of our customers and their systems.

Please note that the released hotfix versions will contain only this one fix (compared to the latest released version) to minimize potential issues.

Solution

ESET will release fixed applications listed below as mandatory Security and Stability hotfixes.

It is important not to run the update from an installer file (for example, via ESET PROTECT's Software Install Task). In this case, the product would run into the issue described above. Wait for the auto-update to be applied automatically and then restart the computer when prompted.

• ESET Endpoint Antivirus and ESET Endpoint Security for Windows 12.1.2076.1 (released on March 24, 2026)

• ESET Server Security for Microsoft Windows Server (the version and release date to be announced)

• ESET Mail Security for Microsoft Exchange Server (the version and release date to be announced)

• ESET Security for Microsoft SharePoint Server (the version and release date to be announced)

For new installations, we recommend using the latest installers downloaded from www.eset.com or the ESET repository.

Affected ESET products

• ESET Endpoint Antivirus and ESET Endpoint Security for Windows 12.1.2076.0

• ESET Server Security for Microsoft Windows Server 12.1.12012.0

• ESET Mail Security for Microsoft Exchange Server 12.1.10010.0

• ESET Security for Microsoft SharePoint Server 12.1.15006.0

Feedback & Support

If you have feedback or questions about this issue, contact us using the ESET Security Forum, or via local ESET Technical Support.

Version log

• Version 1.2 (March 24, 2026): Added an explicit prompt not to run an installer file

• Version 1.1 (March 23, 2026): Clarified the wording of the Summary section

• Version 1.0 (March 23, 2026): Initial version of this document