CVE-2025-34521

CVE-2025-34521 is a medium-severity vulnerability in Arcserve Udp with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

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.

Frequently asked questions

What is CVE-2025-34521?
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.
How severe is CVE-2025-34521?
CVE-2025-34521 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2025-34521 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-34521?
CVE-2025-34521 primarily affects Arcserve Udp. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-34521?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-34521 have an EU (EUVD) identifier?
Yes. CVE-2025-34521 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-27846.
When was CVE-2025-34521 published?
CVE-2025-34521 was published on 2025-08-27 and last updated on 2026-06-17.

References

Affected products (4)

More vulnerabilities in Arcserve Udp

All CVEs affecting Arcserve Udp →

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

Browse all CWE-79 (Cross-site Scripting (XSS)) vulnerabilities →