---
id: CVE-2025-34520
title: >-
  An authentication bypass vulnerability in Arcserve Unified Data Protection
  (UDP) allows unauthenticated attackers to gain unauthorized access to
  protected functionality or user accounts
summary: >-
  An authentication bypass vulnerability in Arcserve Unified Data Protection
  (UDP) allows unauthenticated attackers to gain unauthorized access to
  protected functionality or user accounts. By manipulating specific request
  parameters or exp…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-288
vendor: arcserve
product: udp
affected:
  - udp < 7.0
  - 'udp >= 8.0, < 10.2'
  - udp = 7.0
patched:
  - udp 10.2
published: '2025-08-27'
updated: '2026-09-26'
sourceUpdated: '2026-09-26T00:10:00.127'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-34520'
references:
  - url: >-
      https://support.arcserve.com/s/article/Important-Security-Bulletin-Must-read-for-all-Arcserve-UDP-customers-on-all-versions
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00369
epssPercentile: 0.28045
ingestedAt: '2026-09-26T00:22:39.867Z'
---

## Overview

An authentication bypass vulnerability in Arcserve Unified Data Protection (UDP) allows unauthenticated attackers to gain unauthorized access to protected functionality or user accounts. By manipulating specific request parameters or exploiting a logic flaw, an attacker can bypass login mechanisms without valid credentials and access administrator-level features. This vulnerability affects all UDP versions prior to 10.2. UDP 10.2 includes the necessary patches and requires no action. Versions 8.0 through 10.1 are supported and require either patch application or upgrade to 10.2. Versions 7.x and earlier are unsupported or out of maintenance and must be upgraded to 10.2 to remediate the issue.

## Affected

- `udp < 7.0`
- `udp >= 8.0, < 10.2`
- `udp = 7.0`

## Remediation

Upgrade past the affected range:

- `udp 10.2`