CVE-2026-1801
libsoup: libsoup: HTTP Request Smuggling via malformed chunk headers
Severity
LowRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · February 3, 2026
Updated · July 3, 2026
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.
Statement
This issue has a LOW impact. The libsoup library is vulnerable to HTTP Request Smuggling due to non-RFC-compliant parsing of chunk headers. While exploitation is possible remotely without authentication, the impact on Red Hat products is limited as the SoupServer component, which is affected by this flaw, is not commonly deployed in internet-facing infrastructure.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVSS / CWE
CVSS 3.1 · 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')