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CVE-2026-9780

Status: AnalyzedHigh (8.8)—

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.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

XSS en página web (CWE-79) con interacción del usuario → T1189. Bypass de autenticación (T1078) + ejecución de código arbitrario en SYSTEM (impacto secundario T1059), aunque se menciona 'script' de forma genérica, no JavaScript específico del navegador.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

User TrainingRestrict Web-Based ContentPrivileged Account ManagementApplication Developer GuidanceActive Directory ConfigurationUser Account Management

Affected technologies (1)

Quest — Netvault Backup

CWEs

References

Raw JSON (NVD)

Show
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