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.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-wmj6-g64g-j7q5 sanic chunked trailer request smuggling allows hidden second request execution
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

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 : Received

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

Modified: 2026-09-17T20:18:48.810

Link: CVE-2026-85078

cve-icon Redhat

Severity : Important

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

Links: CVE-2026-85078 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-18T20:02:11Z

Weaknesses