CVE-2026-1801: gnome libsoup HTTP Request/Response Smuggling

Vulnerability summary

CVE-2026-1801 is a medium (CVSS 6.5) HTTP Request/Response Smuggling vulnerability in gnome libsoup. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 35.6% of scored vulnerabilities.

Timeline

1. 03-02-2026
   PublishedVulnerability first disclosed.
2. 26-03-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP requests from a single network message, potentially leading to information disclosure.

• 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.