elixir-mint up to 1.10.x HTTP lib/mint/http1.ex message_body improper synchronization

Summaryinfo

A vulnerability, which was classified as critical, has been found in elixir-mint mint up to 1.10.x. Affected by this issue is the function message_body of the file lib/mint/http1.ex of the component HTTP Handler. Performing a manipulation results in improper synchronization. This vulnerability is reported as CVE-2026-94194. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in elixir-mint mint up to 1.10.x. It has been classified as critical. This affects the function message_body of the file lib/mint/http1.ex of the component HTTP Handler. The manipulation with an unknown input leads to a improper synchronization vulnerability. CWE is classifying the issue as CWE-662. The product utilizes multiple threads or processes to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in elixir-mint mint allows a malicious HTTP/1 server to desynchronize an intermediary and the Mint client on a pooled connection, poisoning the responses to subsequent requests that share the connection. message_body/1 in lib/mint/http1.ex selects chunked framing when chunked is the first coding listed in a response's Transfer-Encoding fields. RFC 9112 section 6.3 applies chunked framing only when chunked is the final coding, and otherwise reads the body until the server closes the connection. For a response such as Transfer-Encoding: chunked, gzip, an intermediary that follows the RFC treats every byte up to the close as the body, while Mint ends the body at the zero-length chunk and parses the remaining bytes as the response to the next request on the connection. Mint also keeps the connection open after an HTTP/1.0 response, final or 1xx, that carries Transfer-Encoding and Connection: keep-alive. RFC 9112 section 6.1 requires treating the framing of such a message as faulty and closing the connection after it, so bytes after its chunked body are parsed as the response to the next request in the same way. This issue affects mint: from 0.1.0 before 1.11.0.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-94194 since 09/24/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 1.11.0 eliminates this vulnerability.

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Productinfo

Vendor

• elixir-mint

Name

• mint

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10

Website

• Product: https://github.com/elixir-mint/mint/

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