CVE-2026-128125

Published Nov 13, 2026 Modified Nov 13, 2026 CWE-1325

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Set-Cookie parsing treats unrecognized name=value attributes as additional cookies, while CookieJar does not limit the number of cookies stored or sent. A malicious server can make an aiohttp client accumulate a very large cookie set, consume memory and CPU repeatedly across redirects, and construct an excessively large Cookie header for later requests to the same domain. This issue is fixed in version 3.14.4.

Is your site exposed to CVE-2026-128125?

Run a free security scan — no signup, results in seconds.

Weakness Type (CWE)

CWE-1325 CWE-1325

References

Frequently Asked Questions

What is CVE-2026-128125? +
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Set-Cookie parsing treats unrecognized name=value attributes as additional cookies, while CookieJar does not limit the number of cookies stored or sent. A malicious server can make an aiohttp client accumulate a very large cookie set, consume memory and CPU repeatedly across redirects, and construct an excessively large Cookie header for later requests to the same domain. This issue is fixed in version 3.14.4.
How do I check if I'm vulnerable to CVE-2026-128125? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2026-128125 — free, no signup required.

Patch and protect

Block known exploits with a web application firewall while you patch, keep your own devices clean, or test the fix on a fresh server.

Compare VPS prices →

Affiliate links: we may earn a commission, your price stays the same.