CVE-2026-2708: gnome libsoup HTTP Request/Response Smuggling

Vulnerability summary

CVE-2026-2708 is a medium (CVSS 5.3) HTTP Request/Response Smuggling vulnerability in gnome libsoup. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 23.6% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 23-04-2026
   PublishedVulnerability first disclosed.
2. 24-04-2026
   Last modifiedVulnerability information updated.

Description

A request smuggling vulnerability exists in libsoup's HTTP/1 header parsing logic. The soup_message_headers_append_common() function in libsoup/soup-message-headers.c unconditionally appends each header value without validating for duplicate or conflicting Content-Length fields. This allows an attacker to send HTTP requests containing multiple Content-Length headers with differing values.

• CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.