CVE-2014-2683 in Zend
Summary
by MITRE
Zend Framework 1 (ZF1) before 1.12.4, Zend Framework 2 before 2.1.6 and 2.2.x before 2.2.6, ZendOpenId, ZendRest, ZendService_AudioScrobbler, ZendService_Nirvanix, ZendService_SlideShare, ZendService_Technorati, and ZendService_WindowsAzure before 2.0.2, ZendService_Amazon before 2.0.3, and ZendService_Api before 1.0.0 allow remote attackers to cause a denial of service (CPU consumption) via (1) recursive or (2) circular references in an XML entity definition in an XML DOCTYPE declaration, aka an XML Entity Expansion (XEE) attack. NOTE: this issue exists because of an incomplete fix for CVE-2012-6532.
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Analysis
by VulDB Data Team • 04/24/2026
The vulnerability described in CVE-2014-2683 represents a critical XML Entity Expansion (XEE) flaw affecting multiple components of the Zend Framework ecosystem. This vulnerability specifically targets the parsing of XML documents within various Zend Framework modules including ZendOpenId, ZendRest, and numerous ZendService components. The issue manifests when malformed XML documents containing recursive or circular references in XML entity definitions are processed, leading to excessive CPU consumption and potential denial of service conditions. The vulnerability was particularly concerning because it represented an incomplete fix for a previously addressed issue, CVE-2012-6532, which had already demonstrated the serious security implications of XML parsing vulnerabilities in web applications.
The technical implementation of this vulnerability exploits the fundamental XML parsing mechanisms used by these framework components. When an XML document containing malicious entity definitions is processed, the parser attempts to resolve entity references recursively, creating a cascade of entity expansions that can consume excessive computational resources. This occurs because the XML parser does not properly limit the depth or number of entity expansions allowed during parsing operations. The circular references in entity definitions cause the parser to enter infinite loops or significantly deep recursion, leading to CPU exhaustion. This type of vulnerability falls under CWE-400, which specifically addresses unchecked resource consumption, and is classified as a denial of service attack vector. The attack can be executed remotely by sending specially crafted XML payloads to any application that processes XML input through the affected Zend Framework components.
The operational impact of CVE-2014-2683 extends far beyond simple service disruption, as it can effectively cripple web applications that rely on XML processing capabilities. Applications using affected versions of Zend Framework components become vulnerable to attacks that can consume system resources at rates that can exhaust server capacity, making the application unavailable to legitimate users. The vulnerability affects a broad range of services including audio scrobbling, cloud storage APIs, social media integration services, and various web service endpoints. Security professionals should note that this vulnerability can be exploited in conjunction with other attack vectors, potentially allowing attackers to cause more severe system degradation. The fact that this vulnerability was introduced by an incomplete fix for CVE-2012-6532 demonstrates the complexity of addressing XML parsing security issues and highlights the importance of thorough testing and validation of security patches.
Mitigation strategies for this vulnerability require immediate patching of affected Zend Framework components to versions that properly address the XML entity expansion issue. Organizations should prioritize updating all affected modules including Zend Framework 1 versions before 1.12.4, Zend Framework 2 versions before 2.1.6 and 2.2.x before 2.2.6, and all the specific ZendService components mentioned. Additionally, implementing XML parser configuration changes that limit entity expansion depth and total entity size can provide defense in depth. Security measures should include input validation and sanitization of all XML content, particularly when processing external data sources. The ATT&CK framework categorizes this vulnerability under T1499.004, which covers network denial of service, and T1595.001, which addresses network infiltration through XML parsing vulnerabilities. Organizations should also consider implementing rate limiting and monitoring for unusual CPU consumption patterns that might indicate exploitation attempts. Regular security assessments of XML processing components and comprehensive vulnerability scanning should be conducted to identify any remaining instances of the vulnerable code within application environments.