Vulnerability · Published Jun 24, 2026 · Assigned by zdi

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

High 8.8

In plain English

A high-severity cross-site scripting in NetVault Backup from Quest. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 61% of all known vulnerabilities).

Severity (CVSS 3.0)8.8High

Exploit odds (30 days)0.9%top 39.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
Quest	NetVault Backup	14.0.1.7

Weakness: CWE-79 · Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References

ZDI-26-369 x_research-advisory
vendor-provided URL vendor-advisory