GNOME SoupServer Persistent Connection request smuggling

Summaryinfo

A vulnerability was found in GNOME SoupServer and classified as critical. This issue affects some unknown processing of the component Persistent Connection Handler. Executing a manipulation can lead to request smuggling. This vulnerability is tracked as CVE-2026-1760. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in GNOME SoupServer (the affected version is unknown) and classified as critical. This vulnerability affects an unknown code of the component Persistent Connection Handler. The manipulation with an unknown input leads to a request smuggling vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

A flaw was found in SoupServer. This HTTP request smuggling vulnerability occurs because SoupServer improperly handles requests that combine Transfer-Encoding: chunked and Connection: keep-alive headers. A remote, unauthenticated client can exploit this by sending specially crafted requests, causing SoupServer to fail to close the connection as required by RFC 9112. This allows the attacker to smuggle additional requests over the persistent connection, leading to unintended request processing and potential denial-of-service (DoS) conditions.

The advisory is shared for download at access.redhat.com. This vulnerability was named CVE-2026-1760 since 02/02/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 03/19/2026).

The vulnerability scanner Nessus provides a plugin with the ID 300863 (SUSE SLED15 / SLES15 / openSUSE 15 Security Update : libsoup (SUSE-SU-2026:0788-1)), 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 (300863) and EUVD (EUVD-2026-5105). Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• GNOME

Name

• SoupServer

License

• open-source

Website

• Vendor: https://www.gnome.org/

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Once again VulDB remains the best source for vulnerability data.

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