CVE-2026-34519
Medium
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.
SeverityMedium
CVSS5.3
Exploit probability—
ProductAiohttp
PublishedApr 1, 2026
First seenApr 1, 2026
Weakness typeCWE-113CWE-113
How to fix
Update
- aiohttp aiohttp3.13.4 or later
- aiohttp3.13.4 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| aiohttp aiohttp | v < 3.13.4 | 3.13.4 |
| aiohttpPyPI | v < 3.13.4 | 3.13.4 |
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