actix actix-http up to 3.12.0 HTTP1.1 Parser request smuggling

Summaryinfo

A vulnerability classified as problematic has been found in actix actix-http up to 3.12.0. The affected element is an unknown function of the component HTTP1.1 Parser. The manipulation leads to request smuggling. This vulnerability is documented as CVE-2026-73051. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in actix actix-http up to 3.12.0 and classified as problematic. This issue affects some unknown processing of the component HTTP1.1 Parser. 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 integrity. The summary by CVE is:

actix-http versions before 3.12.1 contain an HTTP request smuggling vulnerability in the HTTP/1.1 parser that accepts requests with both Content-Length and Transfer-Encoding: chunked headers. Unauthenticated remote attackers can exploit this through a front-end intermediary to desynchronize backend requests and smuggle malicious HTTP requests to the Actix service.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-73051 since 08/10/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 3.12.1 eliminates this vulnerability.

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Productinfo

Vendor

• actix

Name

• actix-http

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12.0

CPE 2.3info

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CPE 2.2info

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