CVE-2016-2366 in Pidgin
Summary
by MITRE
A denial of service vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent via the server could potentially result in an out-of-bounds read. A malicious server or an attacker who intercepts the network traffic can send invalid data to trigger this vulnerability and cause a crash.
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Analysis
by VulDB Data Team • 04/20/2025
The CVE-2016-2366 vulnerability represents a critical denial of service flaw within Pidgin's implementation of the MXIT protocol, which is a proprietary instant messaging protocol used by the MXit messaging service. This vulnerability specifically affects the way Pidgin processes incoming MXIT protocol data, creating a potential attack surface that can be exploited by malicious actors to disrupt service availability. The MXIT protocol integration in Pidgin was designed to provide interoperability with the MXit messaging platform, but the implementation contained a fundamental flaw in its data parsing logic that could be leveraged for malicious purposes.
The technical root cause of this vulnerability stems from inadequate bounds checking during the processing of MXIT protocol messages. When Pidgin receives specially crafted MXIT data from a server, the application fails to properly validate the size and structure of incoming data fields before attempting to read from memory locations. This leads to an out-of-bounds read condition where the program attempts to access memory beyond the allocated buffer boundaries. Such memory access violations typically occur when the application assumes certain data structures will contain specific amounts of data without proper validation, allowing an attacker to manipulate the data flow and trigger unexpected behavior in the application's memory management system. This flaw aligns with CWE-129, which addresses improper validation of array indices and other bounds checking issues that can lead to memory corruption vulnerabilities.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited through network interception attacks or by compromising the MXit server itself. An attacker who successfully exploits this vulnerability can cause Pidgin to crash and terminate unexpectedly, effectively rendering the instant messaging client unusable for the affected user. This denial of service condition can be particularly problematic in environments where Pidgin serves as a primary communication tool, as it can disrupt business operations, personal communications, and collaborative activities. The vulnerability is particularly concerning because it requires no special privileges to exploit, making it accessible to anyone who can intercept network traffic or compromise a MXit server. The attack vector is straightforward and reliable, as it only requires sending malformed MXIT protocol data to trigger the out-of-bounds read condition that causes the application to crash.
Mitigation strategies for CVE-2016-2366 should focus on both immediate defensive measures and long-term architectural improvements. The most effective immediate solution involves updating Pidgin to a version that contains proper bounds checking and input validation for MXIT protocol data processing. System administrators should also implement network monitoring to detect and block suspicious MXIT protocol traffic patterns that might indicate exploitation attempts. Additionally, users should be educated about the risks of connecting to untrusted MXit servers or accepting messages from unknown sources. From a defensive perspective, this vulnerability demonstrates the importance of implementing proper input sanitization and bounds checking mechanisms, which aligns with ATT&CK technique T1499.002 for network denial of service attacks. Organizations should also consider implementing network segmentation and traffic filtering to prevent malicious MXIT data from reaching vulnerable Pidgin installations. The vulnerability serves as a reminder of the critical need for comprehensive security testing of third-party protocol implementations and the importance of maintaining up-to-date software to protect against known vulnerabilities in messaging applications.