In this comprehensive long read post, we will delve into the details of a vulnerability identified as CVE-2025-27113, which has been discovered in libxml2, a widely used XML parsing library. The flaw is due to a NULL pointer dereference error that could potentially allow attackers to execute arbitrary code on a vulnerable system or cause a denial of service (DoS) attack. We will examine the affected versions, the vulnerable code snippet, exploit details, and the original references to ensure that you have a complete understanding of this critical vulnerability.

Affected Versions

According to the security advisories, libxml2 versions before 2.12.10 and 2.13.x before 2.13.6 are affected by the NULL pointer dereference issue in the xmlPatMatch function within pattern.c. If you are using any of these versions, you are urged to upgrade immediately in order to mitigate the risk associated with this vulnerability.

Vulnerable Code Snippet

The vulnerability is due to a NULL pointer dereference issue in the 'xmlPatMatch' function of 'pattern.c' file. Here is a snippet of the vulnerable code:

int
xmlPatMatch(xmlNodePtr node, xmlNodePtr pattern) {
    if ((node == NULL) || (pattern == NULL)) return(-1);
    return (__xmlPatMatch(node, pattern);
}

In the code above, the 'xmlPatMatch' function is called to match an XML node with the given pattern. However, the function does not properly handle the case when either the node or the pattern is NULL, causing a NULL pointer dereference.

Exploit Details

An attacker who successfully exploits this vulnerability will have the ability to cause a DoS attack or potentially execute malicious code on the vulnerable system. The NULL pointer dereference issue can be triggered by crafting a malformed XML document that consists of a particular pattern and node structure.

Upon successful exploitation, an arbitrary code execution may occur, allowing an attacker to take full control of the targeted system. A denial of service attack is also possible as a result of this vulnerability, which can cause unresponsiveness or crashes in affected applications using libxml2.

For further information, the original source of the vulnerability can be found at the following references:

1. Libxml2 Security Advisories: http://xmlsoft.org/news.html
2. National Vulnerability Database (NVD): https://nvd.nist.gov/vuln/detail/CVE-2025-27113
3. Mitre Corporation's CVE Entry: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-27113
4. Libxml2 GitHub Repository: https://github.com/GNOME/libxml2

Conclusion

CVE-2025-27113 is a critical vulnerability in libxml2, affecting a wide range of applications and systems that utilize this popular XML parsing library. It is crucial for developers and system administrators to be aware of this security flaw and update their systems promptly in order to avoid potential attacks.

Remember to stay up to date with the latest security advisories and patch all your software to ensure protection against these types of vulnerabilities. Regularly monitoring and scanning your systems for issues like CVE-2025-27113 will also help in maintaining a more secure environment.

Timeline

Published on: 02/18/2025 23:15:10 UTC
Last modified on: 03/07/2025 01:15:12 UTC