GNOME libsoup non-libsoup Backend soup_body_input_stream_read_chunked request smuggling

Summaryinfo

A vulnerability described as critical has been identified in GNOME libsoup. This vulnerability affects the function soup_body_input_stream_read_chunked of the component non-libsoup Backend Handler. Such manipulation leads to request smuggling. This vulnerability is documented as CVE-2026-6324. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in GNOME libsoup (unknown version) and classified as critical. Affected by this issue is the function soup_body_input_stream_read_chunked of the component non-libsoup Backend Handler. The manipulation with an unknown input leads to a request smuggling vulnerability. Using CWE to declare the problem leads to CWE-444. 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. Impacted is confidentiality, integrity, and availability. CVE summarizes:

A flaw was found in libsoup. A remote attacker could exploit an unsigned to signed conversion error in the `soup_body_input_stream_read_chunked()` function by sending a malicious HTTP request. This vulnerability occurs when libsoup operates behind a non-libsoup proxy server or as a proxy in front of a non-libsoup backend server. Successful exploitation can allow an attacker to bypass security controls, poison web caches, or gain unauthorized access.

The advisory is available at access.redhat.com. This vulnerability is handled as CVE-2026-6324 since 04/14/2026. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/01/2026).

The vulnerability scanner Nessus provides a plugin with the ID 317955 (Linux Distros Unpatched Vulnerability : CVE-2026-6324), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (317955) and EUVD (EUVD-2026-33249). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• GNOME

Name

• libsoup

License

• open-source

Website

• Vendor: https://www.gnome.org/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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