Backblaze Client for Windows Improper Link Resolution Vulnerability (CVE-2026-19820) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-19820

Backblaze Client for Windows Improper Link Resolution Vulnerability

Answer in brief

CVE-2026-19820 records a Unknown severity vulnerability in Backblaze Client for Windows Improper Link Resolution Vulnerability. The current sources do not mark it as known exploited. The current feed maps Backblaze/Backblaze Client (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 1, 2026Updated Sep 1, 2026Source checked Sep 1, 2026First seen by HOL Sep 1, 2026Material review Sep 1, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Backblaze/Backblaze Client (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Backblaze/Backblaze Clientgeneric	10.0.0.1029 \|\| 10.0.1.10307 \|\| 10.0.2.1047	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Backblaze/Backblaze Client.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 1, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.