CVE-2026-50269: CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection') in aio-libs aiohttp
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.0, attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar. In the unlikely situation that an application is passing user-controlled strings into MultipartWriter.append(headers=...) or Payload.headers, then an attacker may be able to modify the request to inject headers or change the contents of the request. This vulnerability is fixed in 3.14.0.
AI Analysis
Technical Summary
The vulnerability CVE-2026-50269 affects aiohttp versions prior to 3.14.0. It involves improper neutralization of CRLF sequences (CWE-93) in multipart or payload headers. If an application passes user-controlled input into MultipartWriter.append(headers=...) or Payload.headers, an attacker could inject additional HTTP headers or alter the request content by exploiting CRLF injection. This could lead to HTTP header injection attacks. The vulnerability is resolved in version 3.14.0 of aiohttp.
Potential Impact
The impact is limited to applications that explicitly pass user-controlled strings into multipart or payload headers in aiohttp. Successful exploitation could allow an attacker to inject additional HTTP headers or modify request contents, potentially affecting request integrity. The CVSS score is low (2.7), indicating limited impact and exploitability.
Mitigation Recommendations
A fix is available in aiohttp version 3.14.0. Users should upgrade to version 3.14.0 or later to remediate this vulnerability. If upgrading is not immediately possible, avoid passing user-controlled input into MultipartWriter.append(headers=...) or Payload.headers to prevent exploitation.
CVE-2026-50269: CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection') in aio-libs aiohttp
Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.0, attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar. In the unlikely situation that an application is passing user-controlled strings into MultipartWriter.append(headers=...) or Payload.headers, then an attacker may be able to modify the request to inject headers or change the contents of the request. This vulnerability is fixed in 3.14.0.
CVSS v4.0
Score 2.7low
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-50269 affects aiohttp versions prior to 3.14.0. It involves improper neutralization of CRLF sequences (CWE-93) in multipart or payload headers. If an application passes user-controlled input into MultipartWriter.append(headers=...) or Payload.headers, an attacker could inject additional HTTP headers or alter the request content by exploiting CRLF injection. This could lead to HTTP header injection attacks. The vulnerability is resolved in version 3.14.0 of aiohttp.
Potential Impact
The impact is limited to applications that explicitly pass user-controlled strings into multipart or payload headers in aiohttp. Successful exploitation could allow an attacker to inject additional HTTP headers or modify request contents, potentially affecting request integrity. The CVSS score is low (2.7), indicating limited impact and exploitability.
Mitigation Recommendations
A fix is available in aiohttp version 3.14.0. Users should upgrade to version 3.14.0 or later to remediate this vulnerability. If upgrading is not immediately possible, avoid passing user-controlled input into MultipartWriter.append(headers=...) or Payload.headers to prevent exploitation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-04T16:26:05.984Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a39735aeed863c81e396229
Added to database: 06/22/2026, 17:39:38 UTC
Last enriched: 06/22/2026, 18:09:41 UTC
Last updated: 06/22/2026, 22:33:40 UTC
Views: 5
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