CVE-2025-24928 is a stack-based buffer overflow vulnerability identified in the xmlSnprintfElements function of the valid.c source file in libxml2, a widely used XML parsing library maintained by xmlsoft. The flaw exists in versions prior to 2.12.10 and in the 2.13.x series before 2.13.6. The vulnerability arises during Document Type Definition (DTD) validation when processing untrusted XML documents or DTDs. Specifically, improper handling of data during the formatting of XML elements leads to a buffer overflow on the stack, which can be exploited to overwrite memory and potentially execute arbitrary code. This vulnerability is similar in nature to CVE-2017-9047, indicating a recurring issue in the DTD validation logic of libxml2. Exploitation does not require authentication or user interaction but does require that the vulnerable system perform DTD validation on untrusted input, which is a common scenario in XML processing applications such as web services, document converters, and embedded devices. The CVSS v3.1 base score of 7.8 reflects a high severity due to the potential for complete confidentiality and integrity compromise, with no impact on availability. No public exploits are known at this time, but the vulnerability's characteristics make it a significant risk if left unpatched. The absence of patch links in the provided data suggests that users should monitor official xmlsoft channels for updates or apply available patches in versions 2.12.10 and 2.13.6 or later.

The vulnerability allows attackers to execute arbitrary code or cause memory corruption by exploiting a stack-based buffer overflow during DTD validation of untrusted XML inputs. This can lead to full compromise of confidentiality and integrity of affected systems, enabling data theft, unauthorized modifications, or further lateral movement within networks. Systems that automatically parse and validate XML documents with DTDs, such as web servers, middleware, document processing tools, and embedded devices, are at risk. The impact is particularly severe in environments where XML inputs originate from untrusted sources, such as internet-facing services or document ingestion pipelines. Although availability is not directly affected, successful exploitation could lead to system instability or crashes as a side effect. Organizations that rely heavily on libxml2 for XML processing without strict input validation or sandboxing are vulnerable to targeted attacks, potentially affecting sensitive data and critical infrastructure operations.

Organizations should immediately update libxml2 to version 2.12.10 or 2.13.6 and later, where the vulnerability is patched. Until updates are applied, disable DTD validation for XML inputs from untrusted sources to prevent exploitation. Implement strict input validation and sanitization to reject or isolate XML documents containing DTDs from untrusted origins. Employ sandboxing or process isolation for XML parsing components to limit the impact of potential exploitation. Monitor XML processing logs for unusual or malformed DTDs that could indicate exploitation attempts. For embedded or legacy systems where patching is challenging, consider replacing libxml2 with alternative XML parsers that do not perform DTD validation or have no known similar vulnerabilities. Maintain up-to-date intrusion detection and prevention systems with signatures targeting XML-based attacks. Finally, establish a vulnerability management process to track and promptly apply security updates for critical libraries like libxml2.