Overview

A critical vulnerability, known as CVE-2025-11021, has been identified in the widely used libsoup HTTP library. This flaw pertains to the library’s cookie date handling logic, with potential consequences including system compromise and data leakage. This vulnerability is particularly significant due to the widespread usage of the libsoup library in GNOME and other web communication applications.

Vulnerability Summary

CVE ID: CVE-2025-11021
Severity: High (7.5 CVSS)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and unintended disclosure of memory contents

Affected Products

Product | Affected Versions

libsoup | All versions prior to patch

How the Exploit Works

The vulnerability lies in the cookie date handling logic of the libsoup HTTP library. It is triggered when processing cookies with specially crafted expiration dates, leading to an out-of-bounds memory read. This can result in the unintended disclosure of memory contents, potentially exposing sensitive information from the process using libsoup.

Conceptual Example Code

Here is a conceptual example of how a specially crafted cookie might trigger the vulnerability:

GET / HTTP/1.1
Host: vulnerable.example.com
Cookie: session=12345; expires=Thu, 01-Jan-1970 00:00:00 GMT; path=/;

In this example, the `expires` attribute of the cookie has been crafted in such a way to trigger the out-of-bounds memory read in the libsoup HTTP library.

Implications and Mitigations

Successful exploitation of this vulnerability could lead to a potential system compromise or data leakage. This could have severe impacts on the confidentiality, integrity, and availability of the affected system.
Organizations are advised to apply the vendor-released patch as soon as possible. As a temporary mitigation, a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) could be used to detect and block attempts to exploit this vulnerability.