High [CVE-2025-4948] Libsoup: integer underflow in soup_multipart_new_from_message leading to denial of service in libsoup

A flaw was found in the soup_multipart_new_from_message() function of the libsoup HTTP library, which is commonly used by GNOME and other applications to handle web communications. The issue occurs when the library processes specially crafted multipart messages.

Due to improper validation, an internal calculation can go wrong, leading to an integer underflow. This can cause the program to access invalid memory and crash.

As a result, any application or server using libsoup could be forced to exit unexpectedly, creating a denial-of-service (DoS) risk. The Red Hat Product Security team has assessed the severity of this vulnerability as High, given that it can be remotely triggered without authentication or user interaction.

Successful exploitation allows an attacker to crash services or applications relying on libsoup for HTTP multipart message processing. The vulnerability’s root cause is a lack of proper bounds checking that results in an integer underflow and subsequent denial-of-service.

Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-191.

Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 7 Extended Lifecycle Support; Red Hat Enterprise Linux 8.2 Advanced Update Support; Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support; and 9 more.