ZDI-26-377: Quest NetVault Backup viewclient Cross-Site Scripting Authentication Bypass Vulnerability
Source Zero Day Initiative
Not known to be exploited.
Data as of 7 Nov 2026, 23:24 UTC
Rated High by Threat Radar from the Zero Day Initiative text · No CVSS score from NVD or the CNA
- EPSS
- 0.9% chance of exploitation in 30 days – higher than 61% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
Public on cve.org; its publication date is not in this record
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 7 Nov 2026.
What to do
AI-suggested
Quest has issued an official update that corrects this vulnerability. Users should apply the update as detailed in the vendor's release notes at https://support.quest.com/technical-documents/netvault/14.0.2/release-notes#TOPIC-2338529. Applying this update mitigates the risk without requiring additional actions.
Description
A cross-site scripting (XSS) vulnerability in the viewclient webpage of Quest NetVault Backup allows remote attackers to bypass authentication. Exploitation requires user interaction, such as visiting a malicious page or opening a malicious file. The vulnerability stems from improper validation of user-supplied data, enabling script injection. Quest has issued an update to address this issue.