AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. In versions 3.13.2 and below, handling of chunked messages can result in excessive blocking CPU usage when receiving a large number of chunks. If an application makes use of the request.read() method in an endpoint, it may be possible for an attacker to cause the server to spend a moderate amount of blocking CPU time (e.g. 1 second) while processing the request. This could potentially lead to DoS as the server would be unable to handle other requests during that time. This issue is fixed in version 3.13.3.
CVSS Details
- CVSS 4.0 Base Score: 6.6 (MEDIUM)
- CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
- CVSS 3.1 Base Score: 5.3
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade py3-aiohttp | Jan 13, 2026 | Jan 5, 2026 |
| Debian | — | Upgrade python-aiohttp | Jun 2, 2026 | Jun 2, 2026 |
| Splunk | — | Upgrade Splunk Enterprise to version 9.4.9Upgrade Splunk Enterprise to version 9.3.10Upgrade Splunk Enterprise to version 10.0.4Upgrade Splunk Enterprise to version 10.2.1 | Jul 30, 2026 | Jan 5, 2026 |
| Ubuntu | — | Upgrade python3-aiohttp (Ubuntu Pro)Upgrade python3-aiohttp | Feb 17, 2026 | Jan 6, 2026 |
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