CVE-2026-19820

high

Description

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.

References

https://www.backblaze.com/status/update

https://www.backblaze.com/computer-backup/docs/backup-client-release-notes-windows

Details

Source: Mitre, NVD

Published: 2026-09-01

Updated: 2026-09-11

Risk Information

CVSS v2

Base Score: 2.1

Vector: CVSS2#AV:L/AC:L/Au:N/C:N/I:P/A:N

Severity: Low

CVSS v3

Base Score: 7.1

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Severity: High

CVSS v4

Base Score: 7.8

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:L

Severity: High

EPSS

EPSS: 0.00327