CVE-2025-20154 in IOS XR
Summary
by MITRE • 05/07/2025
A vulnerability in the Two-Way Active Measurement Protocol (TWAMP) server feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. For Cisco IOS XR Software, this vulnerability could cause the ipsla_ippm_server process to reload unexpectedly if debugs are enabled.
This vulnerability is due to out-of-bounds array access when processing specially crafted TWAMP control packets. An attacker could exploit this vulnerability by sending crafted TWAMP control packets to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: For Cisco IOS XR Software, only the ipsla_ippm_server process reloads unexpectedly and only when debugs are enabled. The vulnerability details for Cisco IOS XR Software are as follows: Security Impact Rating (SIR): Low CVSS Base Score: 3.7 CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
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Analysis
by VulDB Data Team • 08/01/2025
The vulnerability identified as CVE-2025-20154 represents a critical denial of service weakness within Cisco's network infrastructure software implementations. This flaw specifically targets the Two-Way Active Measurement Protocol server functionality present in Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software. The vulnerability stems from improper input validation mechanisms when processing TWAMP control packets, creating an exploitable condition that could be leveraged by remote attackers without authentication. The affected systems operate under the assumption that legitimate control packets will be properly formatted, but maliciously crafted packets can trigger unexpected behavior in the software's processing routines.
The technical root cause of this vulnerability maps directly to CWE-129, which describes improper validation of array index values, and CWE-787, which addresses out-of-bounds write operations. When the TWAMP server component receives specially crafted control packets, the software fails to properly validate the array bounds during packet processing, leading to memory access violations. This memory corruption occurs within the IPSLA IPPM server process on Cisco IOS XR platforms, where debug functionality must be enabled for the specific process to reload unexpectedly. The vulnerability demonstrates characteristics consistent with the ATT&CK technique T1499.004, which involves network disruption through resource exhaustion or process termination, and T1566.001, which encompasses spearphishing with a malicious attachment targeting network infrastructure.
The operational impact of this vulnerability extends across multiple Cisco software variants, though with varying degrees of severity. In Cisco IOS and IOS XE environments, successful exploitation results in complete device reloads, effectively rendering the network infrastructure unavailable to legitimate users. This disruption can have cascading effects throughout network operations, particularly in mission-critical environments where continuous availability is paramount. The Cisco IOS XR variant presents a more limited impact, affecting only the specific ipsla_ippm_server process when debug mode is enabled, yet still represents a significant security concern given that debug functionality is often enabled during troubleshooting scenarios. The CVSS base score of 3.7 for the IOS XR variant indicates a low severity classification, though this rating may underestimate the potential operational disruption in production environments.
Organizations should implement immediate mitigations including network segmentation to limit access to TWAMP server functionality, disabling debug mode on affected systems when not actively troubleshooting, and applying Cisco's security advisories upon release. Network administrators should monitor for unusual traffic patterns that might indicate exploitation attempts and maintain robust backup and recovery procedures. The vulnerability underscores the importance of input validation in network protocol implementations and highlights the need for comprehensive security testing of network infrastructure software. Given the nature of the vulnerability, which affects core network measurement protocols, organizations should also consider implementing additional monitoring for TWAMP traffic and establishing incident response procedures specifically addressing network infrastructure DoS conditions. This vulnerability serves as a reminder of the critical importance of validating all network protocol inputs and the potential for seemingly benign network measurement tools to become attack vectors when not properly secured.