CVE-2026-59881
Medium
Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.2, the WebSocket client accepts and decompresses frames with the RSV1 bit set even when the permessage-deflate extension was not negotiated, allowing a malicious server to cause unexpected CPU and memory consumption. This issue is fixed in version 3.14.2.
SeverityMedium
CVSS6.9
Exploit probability—
ProductAiohttp
PublishedJul 30, 2026
First seenJul 30, 2026
Weakness typeCWE-20Improper input validation
How to fix
Update
- aiohttp3.14.2 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| aiohttpPyPI | v < 3.14.2 | 3.14.2 |
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