CVE-2025-34521 Arcserve UDP < 10.2 Reflected Cross-Site Scripting (XSS)
Remote attackers can execute arbitrary JavaScript in victims' browsers via crafted links, potentially leading to session hijacking or credential theft.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2025-34521?
CVE-2025-34521 is a medium-severity cross-site scripting vulnerability in Arcserve Unified Data Protection (UDP), published on 27 Aug 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
A reflected cross-site scripting (XSS) vulnerability exists in the web interface of the Arcserve Unified Data Protection (UDP), where unsanitized user input is improperly reflected in HTTP responses. This flaw allows remote attackers with low privileges to craft malicious links that, when visited by another user, execute arbitrary JavaScript in the victim’s browser. Successful exploitation may lead to session hijacking, credential theft, or other client-side impacts. The vulnerability requires user interaction and occurs within a shared browser context. 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.
Weakness: CWE-79
Which versions are affected by CVE-2025-34521?
It affects 1 product.
Products include Arcserve Udp.
How do I fix CVE-2025-34521?
No fix has been published for CVE-2025-34521 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2025-34521 being exploited?
There is no known exploitation of CVE-2025-34521 in the wild and no public exploit code.
Other vulnerabilities in Arcserve Unified Data Protection (UDP)
- CVE-2015-4068 Arcserve Unified Data Protection (UDP) Directory Traversal
- CVE-2024-0799 Authentication Bypass via wizardLogin in Arcserve Unified Data Protection
- CVE-2023-41998 Arcserve UDP Unauthenticated RCE
- CVE-2023-41999 Arcserve UDP Management Authentication Bypass
- CVE-2023-42000 Arcserve UDP Agent Unauthenticated Path Traversal File Upload
Sources
Also known as GHSA-h6g8-8gr5-822r.