What’s Vulnerable › Vulnerabilities

CVE-2026-9780: Quest NetVault Backup addclient3 Cross-Site Scripting Authentication Bypass Vulnerability

• Severity: high (CVSS 8.8 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-25 · updated 2026-10-25
• Weakness: CWE-79

Description

Quest NetVault Backup addclient3 Cross-Site Scripting Authentication Bypass Vulnerability. This vulnerability allows remote attackers to bypass authentication on affected installations of Quest NetVault Backup. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the addclient3 webpage. The issue results from the lack of proper validation of user-supplied data, which can lead to the injection of an arbitrary script. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-27666.

Affected products

• Quest NetVault Backup: before 14.0.2 — fixed in 14.0.2

How to fix

Upgrade to a fixed version: Quest NetVault Backup 14.0.2. Check the vendor advisory for mitigations.

References

• https://support.quest.com/technical-documents/netvault/14.0.2/release-notes#TOPIC-2338529
• https://www.zerodayinitiative.com/advisories/ZDI-26-369/

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