libexpat XML Parser Vulnerabilities

libexpat before version 2.7.5 contains an infinite loop vulnerability triggered during DTD (Document Type Definition) parsing, allowing local attackers to cause a denial of service condition. The vulnerability affects all applications and libraries that depend on libexpat for XML parsing, with a CVSS score of 4.0 reflecting limited severity due to local-only attack vector and availability impact. While the CVSS base score is moderate, the infinite loop condition presents a real denial of service risk for services that parse untrusted XML documents containing malicious DTD content.

libexpat before version 2.7.5 contains a NULL pointer dereference vulnerability in the setContext function that occurs when the library retries operations following an out-of-memory condition. This flaw affects all users of vulnerable libexpat versions and can result in application crashes leading to denial of service. While the CVSS score of 2.9 is low and exploitation requires specific local conditions and high complexity, this vulnerability represents a stability risk for XML parsing operations in memory-constrained or stressed environments.

libexpat before version 2.7.5 contains a NULL pointer dereference vulnerability triggered by malformed XML containing empty external parameter entity content, resulting in denial of service through application crashes. The vulnerability affects all versions of libexpat prior to 2.7.5 across multiple platforms and applications that embed this XML parsing library. An attacker with local access can craft a malicious XML document to crash any application using vulnerable libexpat, though the impact is limited to availability (CVSS 4.0) with no code execution or data compromise possible.