CVE-2026-85078

Description

Sanic is an opensource python web server/framework. In version 25.12.0, Sanic's core HTTP/1.1 chunked-body handling does not fully consume the trailer-part after the terminating zero chunk before reusing the keep-alive connection buffer. A remote unauthenticated client can place attacker-controlled bytes in that trailer region, causing Sanic to parse and route them as a hidden second request after the outer request. This breaks HTTP request-boundary integrity and can provide a request-smuggling primitive when Sanic is deployed behind intermediaries. This issue is fixed in version 25.12.1.

References

• https://github.com/sanic-org/sanic/commit/47349d689d65fa1907977ac100e867894aeafb22
• https://github.com/sanic-org/sanic/commit/69a10d3b06babaa9e5f6d1af577364e9e53b6dea
• https://github.com/sanic-org/sanic/commit/a332796506c7c588b6930b02a8886e43eb8ea8d6
• https://github.com/sanic-org/sanic/pull/3164
• https://github.com/sanic-org/sanic/pull/3165