CVE-2025-34523

Critical

Published: 27 August 2025

Published

27 August 2025

Modified

09 September 2025

KEV Added

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Patch

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CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0053 67.5th percentile

Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-34523 is a critical-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Arcserve Udp. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 32.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190). What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

SI-2 requires timely identification, reporting, and correction of software flaws like this heap-based buffer overflow through patching or upgrading to UDP 10.2.

SI-10 Information Input Validation good match

prevent

SI-10 mandates validation of incoming information from external network interfaces, directly countering the improper bounds checking on attacker-controlled input.

SI-16 Memory Protection good match

prevent

SI-16 enforces memory protections such as ASLR and non-executable heap memory, mitigating heap corruption and potential arbitrary code execution from the overflow.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

Remote unauthenticated heap buffer overflow in network-facing service directly enables exploitation of a public-facing application for RCE or DoS.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

A heap-based buffer overflow vulnerability exists in the exists in the network-facing input handling routines of Arcserve Unified Data Protection (UDP). This flaw is reachable without authentication and results from improper bounds checking when processing attacker-controlled input. By sending specially…

crafted data, a remote attacker can corrupt heap memory, potentially causing a denial of service or enabling arbitrary code execution depending on the memory layout and exploitation techniques used. This vulnerability is similar in nature to CVE-2025-34522 but affects a separate code path or component. No user interaction is required, and exploitation occurs in the context of the vulnerable process. 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.

Deeper analysisAI

CVE-2025-34523 is a heap-based buffer overflow vulnerability in the network-facing input handling routines of Arcserve Unified Data Protection (UDP), stemming from improper bounds checking on attacker-controlled input (CWE-122). It affects all UDP versions prior to 10.2 and carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). The flaw is reachable without authentication and occurs in the context of the vulnerable process, with no user interaction required. It shares similarities with CVE-2025-34522 but impacts a distinct code path.

A remote attacker can exploit this vulnerability by sending specially crafted data over the network, leading to heap memory corruption. Depending on memory layout and exploitation techniques, this may result in denial of service or arbitrary code execution.

The Arcserve security bulletin at https://support.arcserve.com/s/article/Important-Security-Bulletin-Must-read-for-all-Arcserve-UDP-customers-on-all-versions states that UDP 10.2 includes the necessary patches with no further action required. Supported versions 8.0 through 10.1 require patch application or upgrade to 10.2, while unsupported versions 7.x and earlier must be upgraded to 10.2 for remediation.