Is CVE-2026-111749 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-111749 being exploited in the wild.

How severe is CVE-2026-111749?

Medium severity, with a CVSS score of 4, published 19 October 2026.

Which products and versions are affected?

Aio-Libs Aiohttp before 3.14.4; aiohttp (PyPI) <= 3.14.3, ECOSYSTEM:introduced=0,fixed=3.14.4.

Is there a fix for CVE-2026-111749?

Yes. aiohttp (PyPI): upgrade to 3.14.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-111749 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-111749?

Check whether you run Aio-Libs Aiohttp or aiohttp (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-111749: aiohttp host-only cookie scope bypass in subdomain handling

Q: Is there a fix for CVE-2026-111749?

Yes. aiohttp (PyPI): upgrade to 3.14.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-111749 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-111749?

Check whether you run Aio-Libs Aiohttp or aiohttp (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-111749 · Severity: medium · CVSS 4 · Published 2026-10-19

aiohttp is an HTTP client/server framework for Python. A subdomain can strip the host-only protection flag from cookies belonging to a parent domain, allowing broader cookie scope than intended. This affects applications that reflect such cookies to browsers, potentially exposing session data or other sensitive cookie content.

Technologies: Aio-Libs Aiohttp, aiohttp (PyPI). Vendors: Aio-Libs, PyPI.

Quick answers

Is CVE-2026-111749 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-111749 being exploited in the wild.
How severe is CVE-2026-111749?: Medium severity, with a CVSS score of 4, published 19 October 2026.
Which products and versions are affected?: Aio-Libs Aiohttp before 3.14.4; aiohttp (PyPI) <= 3.14.3, ECOSYSTEM:introduced=0,fixed=3.14.4.
Is there a fix for CVE-2026-111749?: Yes. aiohttp (PyPI): upgrade to 3.14.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-111749 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-111749?: Check whether you run Aio-Libs Aiohttp or aiohttp (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

aiohttp (PyPI): upgrade to 3.14.4 or later
```
pip install "aiohttp>=3.14.4"
```

Technical details

The vulnerability allows a subdomain to remove the host-only scope flag from an existing parent-domain cookie via cookie expiration or replacement handling. An attacker who can direct a user to visit an untrusted subdomain can exploit this to change cookie scope, though the impact is limited when applications do not reflect those cookies back to a browser or rely on host-only protection.

Affected products

aio-libs aiohttp before 3.14.4

Identifiers

CVE-2026-111749
GHSA-gx76-c99x-2c96

Timeline

2026-10-19: disclosed

References

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