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.
History

Fri, 18 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
First Time appeared Sanic-org
Sanic-org sanic
Vendors & Products Sanic-org
Sanic-org sanic

Fri, 18 Sep 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Thu, 17 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 17 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
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.
Title sanic chunked trailer request smuggling allows hidden second request execution
Weaknesses CWE-444
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-17T14:28:37.286Z

Updated: 2026-09-17T19:19:53.849Z

Reserved: 2026-09-02T21:21:01.776Z

Link: CVE-2026-85078

cve-icon Vulnrichment

Updated: 2026-09-17T17:06:17.345Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-17T15:16:55.153

Modified: 2026-09-30T17:31:44.573

Link: CVE-2026-85078

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-17T14:28:37Z

Links: CVE-2026-85078 - Bugzilla