This vulnerability arises from an integer type mismatch between the caller and the soup_headers_parse() function in libsoup when handling multipart HTTP messages. The mismatch causes the length parameter to be truncated incorrectly, leading to a heap buffer over-read. Exploitation could result in application crashes or limited disclosure of heap memory data. The CVSS 3.1 base score is 4.2, reflecting a network attack vector with high attack complexity, no privileges required, and requiring user interaction. Confidentiality impact is low, integrity impact is none, and availability impact is low.

A remote attacker can cause an application using libsoup to crash or potentially leak contents of heap memory due to the out-of-bounds read. The confidentiality impact is limited to possible disclosure of some heap memory contents. There is no impact on integrity, and availability impact is limited to application crashes.

Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-12548 for current remediation guidance. No official fix or workaround is explicitly stated in the provided advisory content. Users should monitor the vendor advisory for updates and apply patches once available.