CVE-2026-85078: Sanic-Org Sanic

Medium severity, CVSS 6.5. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Sanic-Org Sanic: before 24.12.1 (fixed in 24.12.1); from 25.12.0, before 25.12.1 (fixed in 25.12.1)

Published 2026-09-17. Last modified 2026-09-30.