Executive brief
AIOHTTP is a popular Python library used to build web servers and clients. A vulnerability in how it handles WebSocket connections allows an attacker to bypass memory safety limits by sending incomplete data packets. This can lead to a denial-of-service (DoS) condition where the server crashes or becomes unresponsive due to excessive memory consumption.
Technical details
A resource exhaustion vulnerability (CWE-770) exists in AIOHTTP's WebSocket implementation. The root cause is a failure to strictly enforce memory usage limits when processing large, incomplete WebSocket frame payloads. An unauthenticated remote attacker can exploit this by initiating a WebSocket connection and sending specially crafted incomplete frames, causing the server to allocate memory beyond configured thresholds. This can lead to a Denial of Service (DoS) via memory exhaustion. The issue is resolved in version 3.14.1 by improving WebSocket frame validation and check mechanisms.
Affected products
- aio-libs aiohttp < 3.14.1
Timeline
- 2026-06-08: advisory: GitHub Security Advisory published
- 2026-06-22: disclosed: NVD publication date
- 2026-06-22: patched: Fix released in version 3.14.1