CVE-2026-4271: gnome libsoup Use After Free

Vulnerability summary

CVE-2026-4271 is a high (CVSS 7.5) Use After Free vulnerability in gnome libsoup. EPSS estimates a 0.86% chance of exploitation in the next 30 days, higher than 57.8% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 17-03-2026
   PublishedVulnerability first disclosed.
2. 19-05-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in libsoup, a library for handling HTTP requests. This vulnerability, known as a Use-After-Free, occurs in the HTTP/2 server implementation. A remote attacker can exploit this by sending specially crafted HTTP/2 requests that cause authentication failures. This can lead to the application attempting to access memory that has already been freed, potentially causing application instability or crashes, resulting in a Denial of Service (DoS).

• CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.