CVE-2026-34519
Received Received - Intake
HTTP Header Injection Vulnerability in AIOHTTP Response Component

Publication date: 2026-04-01

Last updated on: 2026-04-16

Assigner: GitHub, Inc.

Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, an attacker who controls the reason parameter when creating a Response may be able to inject extra headers or similar exploits. This issue has been patched in version 3.13.4.
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Meta Information
Published
2026-04-01
Last Modified
2026-04-16
Generated
2026-06-16
AI Q&A
2026-04-02
EPSS Evaluated
2026-06-15
NVD
CVE-2026-34519
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
aiohttp aiohttp to 3.13.4 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-113 The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.
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Executive Summary

This vulnerability exists in the AIOHTTP framework prior to version 3.13.4. It allows an attacker who controls the 'reason' parameter when creating a Response to potentially inject extra HTTP headers or perform similar exploits.

Impact Analysis

The vulnerability can allow an attacker to inject additional HTTP headers into responses. This could lead to security issues such as header injection attacks, which might be used to manipulate client behavior, bypass security controls, or conduct other malicious activities.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade AIOHTTP to version 3.13.4 or later, where the issue has been patched.

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