A critical security flaw has been discovered in libsoup (CVE-2025-32914), a widely used library to provide HTTP client and server functionality for GNOME-based applications. This vulnerability exposes apps built using the libsoup library to potential out-of-bounds read attacks. This post will discuss the technical details of the flaw, provide a code snippet demonstrating the issue, and share links to original references and additional resources.

Details

The issue lies within the soup_multipart_new_from_message() function, responsible for parsing incoming HTTP messages and creating multipart data objects based on the message contents. A malicious HTTP client can craft a specially-designed message exploiting the function, leading the libsoup server to read out of bounds memory.

This out-of-bounds read may result in denial of service, information leakage, or potentially be chained with other vulnerabilities for more severe impacts.

Here's a simple code snippet that demonstrates the issue

#include <libsoup/soup.h>

int main(int argc, char *argv[])
{
    SoupMessage *message;
    SoupMultipart *multipart;
    gchar *content;

    soup_init();

    content = g_strdup("Content-Type: text/plain\r\n\r\n"
                       "This is a test.");

    message = soup_message_new (SOUP_METHOD_POST, "http://www.example.com/";);
    soup_message_set_request (message, "multipart/form-data",
                              SOUP_MEMORY_TAKE, content,
                              strlen (content));

    multipart = soup_multipart_new_from_message (
                                            message->request_headers,
                                            message->request_body);

    if (multipart)
    {
        soup_multipart_free(multipart);
        g_print("Multipart created successfully.\n");
    }
    else
        g_print("Failed to create multipart.\n");

    g_object_unref (message);

    return ;
}

This example code will compile a basic application that initializes a libsoup-based HTTP client. However, if the content of the message is manipulated, the out-of-bounds read occurs, causing unexpected behavior or even crashing the application.

Exploit Details

In order to exploit this flaw, an attacker would need to craft an HTTP message specifically designed to manipulate the soup_multipart_new_from_message() function into reading out-of-bounds memory. The attacker would then send this message to a vulnerable server or client using the libsoup library, potentially causing denial of service, information leak, or further exploitation in combination with other vulnerabilities.

Original References

1. Libsoup official website
2. CVE-2025-32914
3. GNOME bug tracking system reference

Conclusion and Recommendations

To mitigate this vulnerability, developers using libsoup should patch their version of the library as soon as the fix is publicly available. End-users should update their GNOME-based applications that rely on libsoup, especially those handling HTTP communication. Maintaining a proactive approach by monitoring future updates andCVEs associated with libsoup will help defend against similar vulnerabilities. By staying informed and ensuring that appropriate security measures are taken, the risk of a successful exploitation can be minimized.

Timeline

Published on: 04/14/2025 15:15:25 UTC
Last modified on: 04/15/2025 18:39:27 UTC