CVE-2026-69243: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in aio-libs aiohttp
AIOHTTP 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.
AI Analysis
Technical Summary
The vulnerability in aiohttp before version 3.14.2 involves inconsistent interpretation of HTTP requests during the WebSocket upgrade process. Specifically, if a WebSocket upgrade request contains a body, the HTTP parser may switch protocols before fully receiving the request body. This can result in trailing bytes being processed as upgraded protocol or pipelined data instead of normal HTTP body data, enabling a request smuggling attack. The issue is addressed by the fix in aiohttp 3.14.2.
Potential Impact
An attacker targeting the server-side component of aiohttp could exploit this vulnerability to perform HTTP request smuggling via specially crafted WebSocket upgrade requests. This may lead to unexpected request handling behavior, potentially allowing bypass of security controls or manipulation of HTTP traffic. The CVSS 4.0 base score is 6.3 (medium severity), reflecting network attack vector, high attack complexity, and limited impact on confidentiality and integrity.
Mitigation Recommendations
This vulnerability is fixed in aiohttp version 3.14.2. Users should upgrade to version 3.14.2 or later to remediate this issue. No other official remediation or temporary fixes are indicated. Patch status is confirmed by the vendor advisory stating the fix is included in 3.14.2.
CVE-2026-69243: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in aio-libs aiohttp
Description
AIOHTTP 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.
CVSS v4.0
Score 6.3medium
Affected software
aio-libs
aiohttp
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in aiohttp before version 3.14.2 involves inconsistent interpretation of HTTP requests during the WebSocket upgrade process. Specifically, if a WebSocket upgrade request contains a body, the HTTP parser may switch protocols before fully receiving the request body. This can result in trailing bytes being processed as upgraded protocol or pipelined data instead of normal HTTP body data, enabling a request smuggling attack. The issue is addressed by the fix in aiohttp 3.14.2.
Potential Impact
An attacker targeting the server-side component of aiohttp could exploit this vulnerability to perform HTTP request smuggling via specially crafted WebSocket upgrade requests. This may lead to unexpected request handling behavior, potentially allowing bypass of security controls or manipulation of HTTP traffic. The CVSS 4.0 base score is 6.3 (medium severity), reflecting network attack vector, high attack complexity, and limited impact on confidentiality and integrity.
Mitigation Recommendations
This vulnerability is fixed in aiohttp version 3.14.2. Users should upgrade to version 3.14.2 or later to remediate this issue. No other official remediation or temporary fixes are indicated. Patch status is confirmed by the vendor advisory stating the fix is included in 3.14.2.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-03T19:54:19.852Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a7105c1bf32cb7a3436d7e8
Added to database: 08/03/2026, 21:18:57 UTC
Last enriched: 08/11/2026, 17:51:47 UTC
Last updated: 09/18/2026, 01:17:09 UTC
Views: 41
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