How severe is CVE-2026-69243?

No CVSS score has been assigned to CVE-2026-69243 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-69243?

CVE-2026-69243 affects the following packages: aiohttp (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-69243?

Update aiohttp to 3.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-69243 is resolved across your whole dependency graph.

How do I detect CVE-2026-69243 in my PyPI dependencies?

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.

How do I mitigate CVE-2026-69243 if there is no patch (or I can't update yet)?

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.

Is CVE-2026-69243 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-69243 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-69243?

CVE-2026-69243 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 39th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-69243?

CVE-2026-69243 is classified as CWE-444 (CWE-444). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-69243 published, and has it been updated?

CVE-2026-69243 was published on August 3, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-69243: aiohttp — Fixed in 3.14.2

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-2026-69243.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs39th percentile — riskier than 39% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

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 3.14.2, the HTTP parsers were vulnerable to a request smuggling attack relating to WebSocket upgrades. If using the server-side component, an attacker may be able to execute a request smuggling vulnerability using an edge case in the WebSocket upgrade procedure. A WebSocket upgrade request with a body could cause the parser to switch protocols before the complete request body was received, leaving trailing bytes to be handled as upgraded-protocol or pipelined data rather than normal HTTP body data. This issue is fixed in version 3.14.2.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`aiohttp`	all versions	3.14.2`pip install --upgrade 'aiohttp==3.14.2'`

Detection & mitigation playbook

Open-source dependency

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.
Fix
Update aiohttp to 3.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-69243 is resolved across your whole dependency graph.
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.

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 HatModerate

Moderate impact. This vulnerability in aiohttp's HTTP parser enables request smuggling when the server-side component handles WebSocket upgrade requests containing a body. An attacker could exploit an edge case during protocol switching, causing trailing data to be processed as subsequent requests or upgraded protocol…

Product	Fixed in	Advisory
Red Hat Ansible Automation Platform 2.5 for RHEL 8	`python3.12-aiohttp-0:3.14.3-1.el8ap`	RHSA-2026:59135
Red Hat Ansible Automation Platform 2.6 for RHEL 9	`automation-controller-0:4.7.16-1.el9ap`	RHSA-2026:59136
Red Hat Satellite 6.16 for RHEL 8	`python-aiohttp-0:3.14.3-1.el8pc`	RHSA-2026:63327
Red Hat Satellite 6.17 for RHEL 9	`ansible-core-1:2.16.19-1.el9sat`	RHSA-2026:63387
Red Hat Satellite 6.18 for RHEL 9	`pulpcore-obsolete-packages-0:1.3.1-5.el9pc`	RHSA-2026:63386
Red Hat Satellite 6.19 for RHEL 9	`python3.12-aiohttp-0:3.14.3-1.el9pc`	RHSA-2026:63385
Red Hat AI Inference Server 3.2	`rhaiis/model-opt-cuda-rhel9:1790621714`	RHSA-2026:73859
Red Hat AI Inference Server 3.2	`rhaiis/vllm-cuda-rhel9:1790621718`	RHSA-2026:73929

Frequently Asked Questions

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.2, the HTTP parsers were vulnerable to a request smuggling attack relating to WebSocket upgrades. If using the server-side component, an attacker may be able to execute a request smuggling vulnerability using an edge case in the WebSocket upgrade procedure. A WebSocket upgrade request with a body could cause the parser to switch protocols before the complete request body was received, leaving trailing bytes to be handled as upgraded-protocol or pipelined data rather than normal HTTP body data. This is

O3 Security · Impact-Aware SCA

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CVE-2026-69243 — aiohttp