CVE-2026-19820: Backblaze Client

High severity, CVSS 7.8. EPSS: 0.3% chance of exploitation in the next 30 days.

A vulnerability in the Backblaze Client allows a local user to make the system not bootable by creating a link from Backblaze's folder to Windows OS system files during a backup. Successful exploitation requires an administrator-level system change that results in the absence of specific Windows OS security controls. This vulnerability is due to improper link resolution.

Affected products

• Backblaze Backblaze Client: version 10.0.0.1029 only; version 10.0.1.1037 only; version 10.0.2.1047 only

Published 2026-09-01. Last modified 2026-09-11.