VDB-397502 · CVE-2026-19820 · GCVE-0-2026-19820

Backblaze Client 10.0.0.1029/10.0.1.10307/10.0.2.1047 link following

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
3.4	$0-$5k	0.00

Summaryinfo

A vulnerability classified as problematic was found in Backblaze Client 10.0.0.1029/10.0.1.10307/10.0.2.1047. The affected element is an unknown function. Such manipulation leads to link following. This vulnerability is uniquely identified as CVE-2026-19820. Local access is required to approach this attack. No exploit exists.

Detailsinfo

A vulnerability was found in Backblaze Client 10.0.0.1029/10.0.1.10307/10.0.2.1047. It has been rated as problematic. Affected by this issue is an unknown function. The manipulation with an unknown input leads to a link following vulnerability. Using CWE to declare the problem leads to CWE-59. The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. Impacted is integrity, and availability. CVE summarizes:

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.

The advisory is available at backblaze.com. This vulnerability is handled as CVE-2026-19820 since 08/14/2026. The exploitation is known to be easy. Local access is required to approach this attack. Additional levels of successful authentication are required for exploitation. The technical details are unknown and an exploit is not available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

Backblaze

Name

Client

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.4
VulDB Meta Temp Score: 3.4

VulDB Base Score: 3.4
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Link following
CWE: CWE-59
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

08/14/2026 CVE reserved
09/01/2026 +18 days Advisory disclosed
09/01/2026 +0 days VulDB entry created
09/01/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: backblaze.com
Status: Not defined

CVE: CVE-2026-19820 (🔒)
GCVE (CVE): GCVE-0-2026-19820
GCVE (VulDB): GCVE-100-397502

Entryinfo

Created: 09/01/2026 02:44
Changes: 09/01/2026 02:44 (63)
Complete: 🔍
Cache ID: 216::103