CVE-2019-5815 in libxslt
Summary
by MITRE
Type confusion in xsltNumberFormatGetMultipleLevel prior to libxslt 1.1.33 could allow attackers to potentially exploit heap corruption via crafted XML data.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/26/2024
The vulnerability CVE-2019-5815 represents a critical type confusion issue within the libxslt library's xsltNumberFormatGetMultipleLevel function, affecting versions prior to 1.1.33. This flaw exists in the XSLT processing component that transforms XML documents using XSLT stylesheets, making it particularly dangerous in environments where untrusted XML data is processed. The vulnerability stems from improper type handling during the processing of numeric formatting elements within XSLT transformations, creating opportunities for attackers to manipulate memory structures through carefully crafted XML inputs.
The technical implementation of this vulnerability involves a type confusion scenario where the xsltNumberFormatGetMultipleLevel function fails to properly validate data types during processing of multiple-level numbering formats. When processing XML data containing crafted numeric formatting elements, the function incorrectly interprets memory locations, leading to heap corruption conditions. This type confusion typically occurs when the software expects one data type but receives another, causing memory management errors that can result in arbitrary code execution. The vulnerability is classified under CWE-466 as "Use of Incorrectly Specified Type in Memory Allocation" and aligns with ATT&CK technique T1203 for "Exploitation for Client Execution" through malformed input processing.
The operational impact of CVE-2019-5815 extends across numerous applications and systems that rely on libxslt for XML processing, including web servers, content management systems, and enterprise applications. Attackers can exploit this vulnerability by submitting malicious XML documents containing specially crafted XSLT transformations that trigger the type confusion during numeric format processing. The heap corruption resulting from this vulnerability can lead to denial of service conditions, arbitrary code execution, or information disclosure, depending on the specific system configuration and attack vector. Systems using libxslt for processing untrusted XML content are particularly at risk, as the vulnerability can be exploited through common web application attack vectors such as file uploads, XML injection, or API request manipulation.
Mitigation strategies for CVE-2019-5815 primarily focus on upgrading to libxslt version 1.1.33 or later, which includes patches addressing the type confusion issue. Organizations should also implement input validation measures to filter potentially malicious XML content before processing, particularly when dealing with user-supplied data. Additional protective measures include restricting XML processing capabilities, implementing sandboxing mechanisms for XML transformations, and monitoring for unusual processing patterns that might indicate exploitation attempts. Security teams should also consider deploying web application firewalls and input sanitization tools to detect and block malicious XML payloads targeting this vulnerability. The remediation process should include comprehensive testing of XML processing workflows to ensure that the upgrade does not introduce compatibility issues while effectively addressing the heap corruption vulnerability.