CVE-2022-49043 in libxml2
Summary
by MITRE • 01/26/2025
xmlXIncludeAddNode in xinclude.c in libxml2 before 2.11.0 has a use-after-free.
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Analysis
by VulDB Data Team • 10/07/2025
The vulnerability identified as CVE-2022-49043 represents a critical use-after-free flaw within the libxml2 library's xmlXIncludeAddNode function located in xinclude.c. This issue affects versions prior to 2.11.0 and constitutes a serious memory safety defect that can lead to arbitrary code execution or system compromise. The vulnerability arises from improper memory management during XML processing operations involving XInclude directives, which are used to include external XML documents within a main document structure. When processing malformed or specially crafted XML content that triggers XInclude resolution, the library fails to properly manage memory allocation and deallocation sequences, creating conditions where freed memory regions are subsequently accessed.
The technical nature of this vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software implementations. The flaw occurs during the processing of XML documents that contain XInclude directives, where the xmlXIncludeAddNode function handles the addition of nodes to the XML tree structure. When the processing logic encounters certain edge cases in XML structure or malformed input, it may free memory associated with node objects while still maintaining references to them, or it may attempt to access previously freed memory locations. This memory corruption vulnerability can be exploited by attackers who craft malicious XML content that triggers the vulnerable code path during parsing operations. The operational impact extends across numerous applications and systems that rely on libxml2 for XML processing, including web servers, application frameworks, and security tools that parse XML data from untrusted sources.
The exploitation potential of CVE-2022-49043 is significant within the context of the MITRE ATT&CK framework, particularly under the techniques related to code injection and privilege escalation. Attackers can leverage this vulnerability by providing malicious XML input to applications using vulnerable libxml2 versions, potentially leading to remote code execution on affected systems. The attack surface includes web applications, content management systems, and any software that processes XML content from external sources without proper input validation. Systems running web servers, application servers, or any service that handles XML parsing are at risk, especially when these services process user-supplied XML data or interact with external XML feeds. The vulnerability's impact is amplified by the widespread adoption of libxml2 across various operating systems and software platforms, making it a prime target for exploitation at scale. Organizations should prioritize patching their systems to libxml2 version 2.11.0 or later, which includes the necessary memory management fixes to prevent the use-after-free condition from occurring.
The remediation strategy involves immediate deployment of libxml2 version 2.11.0 or higher, which addresses the memory management issues in the xmlXIncludeAddNode function. System administrators should conduct comprehensive vulnerability assessments to identify all systems using affected libxml2 versions and implement patch management procedures to ensure timely updates. Additionally, input validation and sanitization measures should be strengthened to prevent malicious XML content from reaching the vulnerable parsing functions, although this represents a defensive measure rather than a complete solution. Organizations should also consider implementing network segmentation and monitoring to detect potential exploitation attempts targeting this vulnerability, as the use-after-free nature makes reliable exploitation detection challenging. The vulnerability demonstrates the critical importance of proper memory management in widely-used library components and underscores the need for continuous security auditing of foundational software libraries that form the basis of numerous applications and services.