AIOHTTP: HTTP request smuggling via WebSocket upgrade

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-69243
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-03 21:16:42 UTC
Updated2026-08-03 21:16:42 UTC
DescriptionAIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.2, the HTTP parsers were vulnerable to a request smuggling attack relating to WebSocket upgrades. If using the server-side component, an attacker may be able to execute a request smuggling vulnerability using an edge case in the WebSocket upgrade procedure. A WebSocket upgrade request with a body could cause the parser to switch protocols before the complete request body was received, leaving trailing bytes to be handled as upgraded-protocol or pipelined data rather than normal HTTP body data. This issue is fixed in version 3.14.2.

Risk And Classification

Primary CVSS: v4.0 6.3 MEDIUM from [email protected]

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary6.3MEDIUMCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED6.3MEDIUMCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Aio-libs Aiohttp affected < 3.14.2 Not specified

References

ReferenceSourceLinkTags
github.com/aio-libs/aiohttp/releases/tag/v3.14.2 [email protected] github.com
github.com/aio-libs/aiohttp/security/advisories/GHSA-mfx4-hv73-q22v [email protected] github.com
github.com/aio-libs/aiohttp/pull/13017 [email protected] github.com
github.com/aio-libs/aiohttp/commit/6ae358f0983c3f4d6f67692b2f8e65dc8e091c98 [email protected] github.com
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