CVE-2019-15903 : Security Advisory and Response

In versions of libexpat before 2.2.8, a vulnerability allowed for XML input manipulation leading to a heap-based buffer over-read.

Understanding CVE-2019-15903

This CVE involves a security issue in libexpat versions prior to 2.2.8.

What is CVE-2019-15903?

In libexpat before 2.2.8, a flaw allowed crafted XML input to deceive the parser, causing premature switching from DTD parsing to document parsing. Subsequently, calling XML_GetCurrentLineNumber or XML_GetCurrentColumnNumber consecutively led to a heap-based buffer over-read.

The Impact of CVE-2019-15903

The vulnerability could be exploited to trigger a heap-based buffer over-read, potentially leading to a denial of service or arbitrary code execution.

Technical Details of CVE-2019-15903

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

Crafted XML input could trick the parser into premature switching from DTD parsing to document parsing, resulting in a heap-based buffer over-read when specific functions were called.

Affected Systems and Versions

Product: N/A
Vendor: N/A
Versions: All versions before 2.2.8

Exploitation Mechanism

The vulnerability could be exploited by manipulating XML input to deceive the parser, causing it to switch parsing modes prematurely and leading to a heap-based buffer over-read.

Mitigation and Prevention

Protecting systems from CVE-2019-15903 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update libexpat to version 2.2.8 or later to mitigate the vulnerability.
Monitor vendor advisories and apply patches promptly.

Long-Term Security Practices

Regularly update software and libraries to the latest versions.
Implement secure coding practices to prevent similar vulnerabilities.

Patching and Updates

Apply patches provided by the vendor to address the vulnerability effectively.