CVE-2010-0305 in ejabberd
Summary
by MITRE
ejabberd_c2s.erl in ejabberd before 2.1.3 allows remote attackers to cause a denial of service (daemon crash) via a large number of c2s (aka client2server) messages that trigger a queue overload.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 04/30/2026
The vulnerability identified as CVE-2010-0305 affects ejabberd versions prior to 2.1.3 and specifically targets the ejabberd_c2s.erl module which handles client-to-server communication within the ejabberd instant messaging server. This flaw represents a classic resource exhaustion attack vector that exploits the server's handling of client connections and message processing. The vulnerability occurs during the processing of client-to-server messages where the daemon becomes overwhelmed by an excessive volume of messages, leading to a complete service disruption. The issue stems from inadequate queue management and message processing controls that fail to properly throttle or limit incoming message rates from individual clients or client groups.
The technical implementation of this vulnerability involves the ejabberd_c2s.erl module's insufficient handling of message queuing mechanisms that are designed to manage the flow of communications between XMPP clients and the server. When attackers flood the server with a large number of c2s messages, the internal message queues exceed their operational capacity, causing the daemon process to crash and restart. This behavior aligns with CWE-400 which categorizes resource exhaustion vulnerabilities as those that consume system resources to the point of service unavailability. The flaw demonstrates a lack of proper input validation and rate limiting controls within the message processing pipeline, allowing malicious actors to exploit the system's inability to handle excessive message loads gracefully.
Operationally, this vulnerability presents a significant risk to organizations relying on ejabberd for their instant messaging infrastructure as it can be exploited to perform denial of service attacks against the messaging service. The impact extends beyond simple service disruption to potentially affect business continuity and communication availability for users within the affected organization. Attackers can leverage this vulnerability to target specific ejabberd instances by sending high volumes of client-to-server messages, causing the daemon to become unresponsive and requiring manual intervention to restore service. The attack vector is particularly concerning because it requires minimal technical expertise to execute, making it accessible to a wide range of threat actors. This vulnerability can be categorized under ATT&CK technique T1499.004 which covers network denial of service attacks, specifically targeting service availability through resource exhaustion.
The recommended mitigation strategies include upgrading to ejabberd version 2.1.3 or later where this vulnerability has been addressed through improved queue management and rate limiting mechanisms. Organizations should implement proper message rate limiting at the network level to prevent excessive message volumes from reaching the server. Additionally, administrators should configure appropriate queue size limits and implement monitoring systems to detect unusual message traffic patterns that could indicate an attack attempt. The fix implemented in version 2.1.3 likely includes enhanced queue overflow protection, improved message processing throttling, and better resource management controls within the ejabberd_c2s.erl module. Network administrators should also consider implementing firewalls or load balancers that can detect and filter excessive message traffic patterns to provide additional protection against similar exploitation attempts.