CVE-2014-2289 in Asterisk
Summary
by MITRE
res/res_pjsip_exten_state.c in the PJSIP channel driver in Asterisk Open Source 12.x before 12.1.0 allows remote authenticated users to cause a denial of service (crash) via a SUBSCRIBE request without any Accept headers, which triggers an invalid pointer dereference.
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Analysis
by VulDB Data Team • 05/11/2026
The vulnerability identified as CVE-2014-2289 affects the PJSIP channel driver within Asterisk Open Source version 12.x prior to 12.1.0, representing a critical security flaw that can be exploited by remote authenticated attackers to induce a denial of service condition. This issue specifically resides in the res/res_pjsip_exten_state.c file, which handles extension state subscriptions within the SIP communication framework. The vulnerability manifests when the system receives a SUBSCRIBE request that lacks any Accept headers, creating a scenario where the application fails to properly validate incoming request parameters before attempting to process them. This particular flaw represents a classic example of improper input validation that leads to memory corruption and system instability.
The technical execution of this vulnerability involves an invalid pointer dereference condition that occurs during the processing of SIP SUBSCRIBE requests. When an authenticated user sends a SUBSCRIBE message without specifying Accept headers, the PJSIP channel driver fails to properly handle this edge case in its request parsing logic. The system attempts to access memory locations through pointers that have not been properly initialized or validated, resulting in a segmentation fault that causes the Asterisk process to crash. This behavior aligns with CWE-476, which describes null pointer dereference vulnerabilities, and demonstrates how improper validation of request parameters can lead to system instability. The vulnerability is particularly dangerous because it requires only authenticated access to exploit, meaning that an attacker with valid credentials can disrupt service without requiring additional privileges or complex attack vectors.
From an operational impact perspective, this vulnerability directly compromises the availability of Asterisk-based communication systems, potentially affecting organizations that rely on SIP trunking, VoIP services, or unified communications platforms. The denial of service condition can result in complete disruption of voice communication services, emergency call handling, or business-critical telephony infrastructure. Attackers can repeatedly exploit this vulnerability to maintain persistent service disruption, making it particularly concerning for mission-critical deployments. The impact extends beyond simple service interruption as it can affect emergency services, customer support systems, and enterprise communication networks that depend on stable SIP infrastructure. Organizations using affected versions may experience extended downtime while applying patches, potentially leading to significant business disruption and customer service degradation.
The mitigation strategy for CVE-2014-2289 involves immediate deployment of the patched Asterisk version 12.1.0 or later, which includes proper input validation for SUBSCRIBE requests and handles missing Accept headers gracefully. System administrators should also implement network-level controls to monitor and restrict SIP traffic patterns, particularly focusing on unusual SUBSCRIBE request behaviors that may indicate attempted exploitation. Security monitoring should include detection of malformed SIP requests and implementation of rate limiting for subscription requests to prevent abuse. Organizations should also consider implementing intrusion detection systems that can identify patterns consistent with this vulnerability and establish incident response procedures for rapid remediation. This vulnerability demonstrates the importance of proper input validation in telephony applications and aligns with ATT&CK technique T1499.004, which covers network disruption through denial of service attacks, emphasizing the need for robust error handling in communication protocols to prevent exploitation of memory corruption vulnerabilities.