How severe is CVE-2026-111066?

No CVSS score has been assigned to CVE-2026-111066 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-111066?

CVE-2026-111066 affects the following packages: aiohttp (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-111066?

Update aiohttp to 3.14.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-111066 is resolved across your whole dependency graph.

How do I detect CVE-2026-111066 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-2026-111066 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2026-111066 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-111066 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-2026-111066?

CVE-2026-111066 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 31th 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-2026-111066?

CVE-2026-111066 is classified as Uncontrolled Resource Consumption (CWE-400), CWE-770 (CWE-770). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-111066 published, and has it been updated?

CVE-2026-111066 was published on October 19, 2026 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-111066 — aiohttp

Fix: aio-libs/aiohttp@2d94633

CVE-2026-111066 is a Uncontrolled Resource Consumption vulnerability in aiohttp. A fix is available for aiohttp — see the affected versions and patch details below.

AIOHTTP: File descriptor exhaustion in multipart requests

Also known asGHSA-9xw5-w5jj-pvcg

Published

Oct 19, 2026

Updated

Oct 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 23, 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-2026-111066.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs31th percentile — riskier than 31% 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. From 2.0.0 until 3.14.4, multipart request processing can retain an unbounded number of open file descriptors. An unauthenticated attacker can consequently exhaust file descriptors with specially crafted multipart requests when a handler uses Request.post(). This issue is fixed in version 3.14.4.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`aiohttp`	≥ 2.0.0&&< 3.14.4	3.14.4`pip install --upgrade 'aiohttp==3.14.4'`

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 3.14.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-111066 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

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

Workaround published by Red Hat

--- CME Mitigation Guidance (2026-10-20) --- Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure. The highest-value action is to enforce strict limits on multipart payload sizes and uploaded part counts in request handlers invoking Request.post() to prevent unbounded file descriptor allocation: upgrade to aiohttp 3.14.4 (or the fixed Ansible Automation Platform 24/Lightspeed Rhel/Rhoai/Odh Caikit Tgis Serving…

Source: Red Hat security advisory for CVE-2026-111066 (CC BY 4.0)

Frequently Asked Questions

O3 Security · Impact-Aware SCA

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