Inconsistent interpretation of HTTP requests in libsoup - CVE-2025-14523
Published: December 15, 2025
Vulnerability identifier: #VU119956
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2025-14523
CWE-ID: CWE-444
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Gnome Development Team
Affected software:
libsoup
libsoup
Detailed vulnerability description
The vulnerability allows a remote attacker to perform HTTP request smuggling attacks.
The vulnerability exists due to improper validation of HTTP requests. libsoup accepts duplicate Host: headers and implements a last-value-wins policy when soup_message_headers_get_one[_common] is used to construct the request URI, while many proxies and routers use the first Host: header for routing. A remote attacker can send a specially crafted HTTP request to the server and smuggle arbitrary HTTP headers.
How to mitigate CVE-2025-14523
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.