CVE-2016-2378 in Pidgin
Summary
by MITRE
A buffer overflow vulnerability exists in the handling of the MXIT protocol Pidgin. Specially crafted data sent via the server could potentially result in a buffer overflow, potentially resulting in memory corruption. A malicious server or an unfiltered malicious user can send negative length values to trigger this vulnerability.
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Analysis
by VulDB Data Team • 04/20/2025
The CVE-2016-2378 vulnerability represents a critical buffer overflow flaw within Pidgin's implementation of the MXIT protocol handling mechanism. This vulnerability specifically targets the client-side processing of incoming data packets from MXIT servers, creating a potential pathway for remote code execution or system compromise. The flaw manifests when Pidgin processes malformed data structures containing negative length values that are transmitted through the MXIT protocol, which is a proprietary messaging protocol used by the MXit instant messaging service. The vulnerability stems from inadequate input validation and bounds checking within the protocol parser, allowing attackers to craft malicious payloads that exceed the allocated buffer space.
The technical implementation of this vulnerability involves the manipulation of length fields within MXIT protocol packets that are processed by Pidgin's core messaging engine. When a malicious server or user sends data containing negative length values, the application fails to properly validate these inputs before attempting to allocate memory or process the data. This improper validation leads to a classic buffer overflow condition where the application attempts to write data beyond the boundaries of allocated memory buffers. The CWE-121 classification applies here as this represents a stack-based buffer overflow due to insufficient bounds checking of user-supplied data. The vulnerability specifically aligns with ATT&CK technique T1059.007 for command and script injection, as successful exploitation could enable arbitrary code execution on the victim's system.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates a potential attack vector for remote exploitation in environments where users interact with untrusted MXIT servers or malicious users. The vulnerability is particularly concerning because it can be triggered through legitimate protocol communication channels, making it difficult to detect and prevent through standard network monitoring. An attacker who controls a malicious MXIT server or gains access to a compromised user account can craft specific protocol messages that exploit this vulnerability without requiring user interaction beyond connecting to the malicious service. The memory corruption resulting from this overflow can lead to application crashes, denial of service conditions, or more severe consequences including arbitrary code execution depending on the target system's memory layout and security mitigations. Organizations using Pidgin for MXIT communications face significant risk, as this vulnerability affects a wide range of systems where the application is deployed, particularly in enterprise environments where instant messaging is commonly used for internal communications. The vulnerability's exploitation requires minimal privileges and can be automated, making it particularly dangerous in widespread deployment scenarios where users may unknowingly connect to malicious servers.
Mitigation strategies for CVE-2016-2378 primarily focus on immediate software updates and protocol validation enhancements. Users should upgrade to Pidgin versions that include patches addressing this specific buffer overflow vulnerability, as the official Pidgin development team released fixes that properly validate length fields within MXIT protocol packets. Network administrators should implement strict filtering of MXIT protocol traffic at network boundaries and consider disabling MXIT protocol support entirely if not required for business operations. Additionally, implementing proper input validation and bounds checking within the application's protocol handlers would prevent similar vulnerabilities from occurring in future implementations. Security monitoring should include detection of anomalous length fields in MXIT protocol communications, and system administrators should consider deploying intrusion detection systems that can identify potential exploitation attempts. The vulnerability highlights the importance of proper input validation and memory safety practices in instant messaging applications, particularly those handling external protocol data. Organizations should also consider implementing principle of least privilege for instant messaging applications and regularly audit their messaging protocol support to ensure only necessary protocols are enabled.