CVE-2025-41433 in BIG-IP
Summary
by MITRE • 05/08/2025
When a Session Initiation Protocol (SIP) message routing framework (MRF) application layer gateway (ALG) profile is configured on a Message Routing virtual server, undisclosed requests can cause the Traffic Management Microkernel (TMM) to terminate.
Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
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Analysis
by VulDB Data Team • 10/22/2025
The vulnerability identified as CVE-2025-41433 represents a critical stability issue within F5 BIG-IP systems that operate Session Initiation Protocol message routing frameworks with application layer gateway profiles. This flaw specifically manifests when SIP traffic is processed through a Message Routing virtual server that has an MRF ALG profile configured, creating a potential point of system failure that could disrupt voice and video communication services. The vulnerability stems from improper handling of certain SIP requests within the Traffic Management Microkernel, which serves as the core processing engine for F5's traffic management capabilities. When these undisclosed SIP requests are received, the TMM terminates unexpectedly, leading to service disruption and potential denial of service conditions for legitimate users.
The technical nature of this vulnerability falls under the category of improper input handling and resource management within network infrastructure software. The flaw demonstrates a lack of proper error handling mechanisms in the TMM when processing specific SIP message patterns that are not adequately validated or sanitized before being processed through the MRF ALG profile. This represents a classic example of a buffer over-read or memory corruption scenario where the system attempts to process malformed or unexpected SIP requests that trigger an abrupt termination of the core processing component. The vulnerability is particularly concerning because it occurs at the kernel level within the TMM, making it difficult to predict or prevent through standard application-level protections. According to CWE classification, this vulnerability aligns with CWE-20: Improper Input Validation, and potentially CWE-129: Improper Validation of Array Index, as the system fails to properly validate incoming SIP request parameters before processing them through the MRF framework.
From an operational perspective, this vulnerability poses significant risk to organizations that rely on F5 BIG-IP systems for voice communication services, particularly those implementing SIP trunking or unified communications solutions. The termination of the TMM can result in complete service outages for SIP-based applications, affecting everything from traditional phone systems to modern VoIP services and video conferencing platforms. Attackers could potentially exploit this vulnerability through carefully crafted SIP requests that trigger the TMM termination, creating a persistent denial of service condition that would require manual intervention to restore service. The impact extends beyond simple service disruption as the termination of the core traffic management component could affect other services running on the same system, potentially creating cascading failures throughout the network infrastructure. This vulnerability aligns with ATT&CK technique T1499.004: Endpoint Denial of Service, where the attacker targets system stability through resource exhaustion or component termination.
The recommended mitigation strategies for this vulnerability include immediate deployment of available security patches from F5, which would address the underlying input validation issues and provide proper error handling for the affected SIP request patterns. Organizations should also implement network segmentation and access controls to limit exposure to potentially malicious SIP traffic, particularly when dealing with external SIP peers or untrusted networks. Monitoring and logging of SIP traffic patterns should be enhanced to detect anomalous requests that might trigger the vulnerability, with alerts configured for unusual termination events within the TMM. Additionally, implementing rate limiting and request validation mechanisms at the network perimeter can help prevent exploitation by limiting the volume of potentially malicious requests that reach the vulnerable system. The solution should also include regular system health monitoring to quickly detect and respond to any TMM termination events, ensuring rapid recovery and minimal service disruption. Organizations should conduct thorough testing of the applied patches in controlled environments before deployment to ensure compatibility with existing SIP infrastructure and services.