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🐍 PyPI
Not in CISA KEV

CVE-2026-69244 aiohttp

Fix: aio-libs/aiohttp@49f65d5

CVE-2026-69244 is a Out-of-bounds Read vulnerability in aiohttp. A fix is available for aiohttp — see the affected versions and patch details below.

AIOHTTP: Out-of-bounds heap read in C HTTP response parser error path (malformed chunked response)

Also known asGHSA-cq5v-8q36-5273PYSEC-2026-3545
Published
Aug 3, 2026
Updated
Sep 13, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 17, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-69244.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs23th percentile — riskier than 23% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected
🐍aiohttp

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.3, an out-of-bounds heap read could occur in the C response parser while building an error message for a malformed response. An attacker controlled server, or possibly an accidental response, could trigger a DoS in the client. The vulnerable path was error message construction in aiohttp/_http_parser.pyx, where an llhttp error-position pointer was used to build a snippet for malformed chunked responses and malformed request or response bytes at the buffer end. This issue is fixed in version 3.14.3.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIaiohttpall versions3.14.3pip install --upgrade 'aiohttp==3.14.3'

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aiohttp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update aiohttp to 3.14.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-69244 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-69244 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-69244. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This is an Important severity flaw in aiohttp that could lead to a denial of service in client applications. A remote, malicious HTTP server could send a specially crafted response, causing an out-of-bounds read in the aiohttp C response parser and resulting in the client application terminating unexpectedly.

ProductFixed inAdvisory
Red Hat Ansible Automation Platform 2.5 for RHEL 8automation-controller-0:4.6.32-1.el8apRHSA-2026:59135
Red Hat Ansible Automation Platform 2.6 for RHEL 9automation-controller-0:4.7.16-1.el9apRHSA-2026:59136
Red Hat Satellite 6.16 for RHEL 8python-aiohttp-0:3.14.3-1.el8pcRHSA-2026:63327
Red Hat Satellite 6.17 for RHEL 9ansible-core-1:2.16.19-1.el9satRHSA-2026:63387
Red Hat Satellite 6.18 for RHEL 9pulpcore-obsolete-packages-0:1.3.1-5.el9pcRHSA-2026:63386
Red Hat Satellite 6.19 for RHEL 9python3.12-aiohttp-0:3.14.3-1.el9pcRHSA-2026:63385
Red Hat Ansible Automation Platform 2.18ansible-automation-platform/ee-minimal-rhel8:1786971288RHSA-2026:55853
Red Hat Ansible Automation Platform 2.18ansible-automation-platform/ee-minimal-rhel9:1786942232RHSA-2026:55852

Frequently Asked Questions

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.3, an out-of-bounds heap read could occur in the C response parser while building an error message for a malformed response. An attacker controlled server, or possibly an accidental response, could trigger a DoS in the client. The vulnerable path was error message construction in aiohttp/_http_parser.pyx, where an llhttp error-position pointer was used to build a snippet for malformed chunked responses and malformed request or response bytes at the buffer end. This issue is fixed in version 3.14.3.
O3 Security · Impact-Aware SCA

Is CVE-2026-69244 in your dependencies?

O3 Security finds CVE-2026-69244 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2026-69244: aiohttp DoS | O3 Security