CVE-2019-25544 in Pidgin
Summary
by MITRE • 03/21/2026
Pidgin 2.13.0 contains a denial of service vulnerability that allows local attackers to crash the application by providing an excessively long username string during account creation. Attackers can input a buffer of 1000 characters in the username field and trigger a crash when joining a chat, causing the application to become unavailable.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 03/24/2026
The vulnerability identified as CVE-2019-25544 represents a critical denial of service flaw within Pidgin version 2.13.0 that stems from inadequate input validation during account creation processes. This vulnerability specifically targets the username field handling mechanism where the application fails to properly sanitize or limit the length of user-provided identifiers. The flaw exists in the client-side processing logic that does not implement proper bounds checking for string inputs, creating an exploitable condition that can be leveraged by local attackers to disrupt service availability.
The technical implementation of this vulnerability demonstrates a classic buffer overflow condition that occurs when an attacker provides an excessively long username string of 1000 characters during the account creation phase. This excessive input length triggers an unhandled exception within the application's memory management system, causing the program to terminate unexpectedly and crash. The vulnerability is particularly concerning because it operates at the application level rather than at the network protocol level, making it accessible through local system access rather than remote network exploitation. The crash occurs specifically when attempting to join a chat session, indicating that the vulnerability manifests during runtime processing rather than at initial input capture.
From an operational perspective, this denial of service vulnerability significantly impacts the reliability and availability of the Pidgin messaging client, particularly in environments where multiple users may attempt to access the application simultaneously. The local nature of the attack means that an attacker must already have access to the system, but this access level is often sufficient to cause substantial disruption in collaborative work environments or shared computing resources. The impact extends beyond simple application unavailability to potentially affect communication workflows, especially in scenarios where Pidgin serves as a primary communication channel for team coordination or customer support operations.
The vulnerability aligns with CWE-122, which describes improper restriction of operations within a limited memory buffer, and demonstrates characteristics consistent with CWE-787, indicating an out-of-bounds write condition. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1499.004, which involves network denial of service attacks, though the local execution context makes it more aligned with privilege escalation and local attack vectors. The vulnerability's exploitation requires minimal technical sophistication and can be automated, making it particularly dangerous in environments with multiple concurrent users or in systems where local access is not strictly controlled. The lack of input sanitization creates a persistent risk that can be exploited repeatedly until the underlying code is patched or updated.
Effective mitigation strategies for this vulnerability should focus on implementing strict input validation and length limitation mechanisms within the application's account creation interface. The recommended approach involves establishing maximum character limits for username fields and implementing robust buffer management techniques that prevent memory corruption during string processing. System administrators should prioritize immediate patch deployment for Pidgin 2.13.0 installations and consider implementing additional security controls such as input filtering at the system level or application sandboxing. The vulnerability serves as a reminder of the critical importance of proper input validation and memory management in client applications, particularly those handling user-generated content that may be processed in sensitive operational contexts.