sanic chunked trailer request smuggling allows hidden second request execution

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-85078
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 15:16:55 UTC
Updated2026-09-17 20:18:48 UTC
DescriptionSanic 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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

EPSS: 0.002960000 probability, percentile 0.225230000 (date 2026-09-20)

Problem Types: CWE-444 | CWE-444 CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Sanic-org Sanic affected < 24.12.1 Not specified
CNA Sanic-org Sanic affected >= 25.12.0, < 25.12.1 Not specified

References

ReferenceSourceLinkTags
github.com/sanic-org/sanic/pull/3164 [email protected] github.com
github.com/sanic-org/sanic/security/advisories/GHSA-wmj6-g64g-j7q5 [email protected] github.com
github.com/sanic-org/sanic/commit/47349d689d65fa1907977ac100e867894aeafb22 [email protected] github.com
github.com/sanic-org/sanic/releases/tag/v25.12.1 [email protected] github.com
github.com/sanic-org/sanic/commit/69a10d3b06babaa9e5f6d1af577364e9e53b6dea [email protected] github.com
github.com/sanic-org/sanic/commit/a332796506c7c588b6930b02a8886e43eb8ea8d6 [email protected] github.com
github.com/sanic-org/sanic/pull/3165 [email protected] github.com
github.com/sanic-org/sanic/releases/tag/v24.12.1 [email protected] github.com
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