Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| aio-libs | aiohttp | < 3.13.3 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | python-aiohttp | 3.13.3-1 | — |
| Debian 13 | python-aiohttp | 3.11.16-1+deb13u1 | — |
| Debian 12 | python-aiohttp | 3.8.4-1+deb12u2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 25.10 | python-aiohttp | 3.11.16-1ubuntu0.1 | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | python-aiohttp | 3.9.1-1ubuntu0.1+esm2 | — |
| Ubuntu Pro 22.04 LTS | python-aiohttp | 3.8.1-4ubuntu0.2+esm2 | — |
| Ubuntu Pro 18.04 LTS | python-aiohttp | 3.0.1-1ubuntu0.1~esm6 | — |
| Ubuntu Pro 16.04 LTS | python-aiohttp | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | python-aiohttp | 3.6.0-150100.3.32.1 | SUSE-SU-2026:0859-1 |
| SLES 15 SP6 | python-aiohttp | 3.6.0-150100.3.32.1 | SUSE-SU-2026:0859-1, SUSE-SU-2026:0858-1 |
| SLES 15 SP5 | python-aiohttp | 3.6.0-150100.3.32.1 | SUSE-SU-2026:0859-1, SUSE-SU-2026:0858-1 |
| SLES 15 SP4 | python-aiohttp | 3.6.0-150100.3.32.1 | SUSE-SU-2026:0859-1, SUSE-SU-2026:0858-1 |
| SLES 3 | python-aiohttp | 3.9.3-150400.10.36.1 | SUSE-SU-2026:0858-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | python-Brotli | 1.1.0-160000.3.1 | SUSE-SU-2026:20425-1 |
| SLES for SAP 16.0 | python-aiohttp | 3.11.16-160000.3.1 | SUSE-SU-2026:20425-1 |
| SLES for SAP 15 SP6 | python-aiohttp | 3.9.3-150400.10.36.1 | SUSE-SU-2026:0858-1 |
| SLES for SAP 15 SP5 | python-aiohttp | 3.9.3-150400.10.36.1 | SUSE-SU-2026:0858-1 |
| SLES for SAP 15 SP4 | python-aiohttp | 3.9.3-150400.10.36.1 | SUSE-SU-2026:0858-1 |
| SLES 16.0 | python-Brotli | 1.1.0-160000.3.1 | SUSE-SU-2026:20425-1 |
| SLES 16.0 | python-aiohttp | 3.11.16-160000.3.1 | SUSE-SU-2026:20425-1 |
| SLE HPC 15 SP5 | python-aiohttp | 3.9.3-150400.10.36.1 | SUSE-SU-2026:0858-1 |
| SLE HPC 15 SP4 | python-aiohttp | 3.9.3-150400.10.36.1 | SUSE-SU-2026:0858-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-aiohttp | 3.13.3-1.1 | openSUSE-SU-2026:10025-1 |
| openSUSE Leap 16.0 | python-Brotli | 1.1.0-160000.3.1 | openSUSE-SU-2026:20204-1 |
| openSUSE Leap 16.0 | python-aiohttp | 3.11.16-160000.3.1 | openSUSE-SU-2026:20204-1 |
| openSUSE Leap 15.6 | python-aiohttp | 3.9.3-150400.10.36.1 | SUSE-SU-2026:0858-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | py3-aiohttp | 3.13.3-r0 | — |
| Alpine v3.23 | py3-aiohttp | 3.13.3-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | python-aiohttp | No fix yet | — |
| Azure Linux 2 (CBL-Mariner) | python-aiohttp | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | python39-oci-sdk +1 | 2.187.0-1.0.5.el9 | ELSA-2026-604898 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | airflow-3 | 3.1.5-r2 | — |
| Wolfi rolling | airflow-3-bitnami-compat | No fix yet | — |
| Wolfi rolling | checkov | 3.2.499-r0 | — |
| Wolfi rolling | dask-kubernetes | 2025.7.0-r4 | — |
| Wolfi rolling | kserve-storage-controller | 0.17.0-r2 | — |
| Wolfi rolling | kubeflow-pipelines-visualization-server | 2.15.0-r1 | — |
| Wolfi rolling | open-webui | 0.6.43-r1 | — |
| Wolfi rolling | py3-cassandra-medusa +1 | 0.26.0-r3 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | aiohttp | < 3.13.3 | 3.13.3 | GHSA-g84x-mcqj-x9qq |
Advisories 6
- ELSA-2026-604898 Important: python-oci-sdk security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Oct 21, 2026
- openSUSE-SU-2026:20204-1 Security update for python-aiohttp, python-Brotli SUSE / openSUSE Security Updates · Mar 23, 2026
- openSUSE-SU-2026:10025-1 python311-aiohttp-3.13.3-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20425-1 Security update for python-aiohttp, python-Brotli SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0859-1 Security update for python-aiohttp SUSE / openSUSE Security Updates · Mar 13, 2026
- SUSE-SU-2026:0858-1 Security update for python-aiohttp SUSE / openSUSE Security Updates · Mar 13, 2026