CVE-2026-1801CWE-444

Libsoup: libsoup: http request smuggling via malformed chunk headers

Medium · published February 3, 2026

CVSS v3.1
5.3
EPSS
0%
Percentile
35.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00427 · 35.9th percentile
Weakness
CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Published
2026-02-03T20:12Z
EPSS history
Timeline
  • 03 FEB 20:12Z
    Libsoup: libsoup: http request smuggling via malformed chunk headers
    cvelistv5