CVE-2026-85078

Medium

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.

SeverityMedium

CVSS6.5

Exploit probability—

ProductSanic

PublishedSep 17, 2026

First seenSep 17, 2026

Weakness typeCWE-444CWE-444

How to fix

Update

sanic24.12.1, 25.12.1 or later

Affected products

Product	Affected versions	Fixed in
sanicPyPI	v < 24.12.1, 25.12.0 ≤ v < 25.12.1	24.12.1, 25.12.1

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