CVE-2026-128125
AIOHTTP: Unbounded cookie storage in client CookieJar
- Medium 6.3
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.
Key facts
- Published
- 13 Nov 2026
- Last changed
- 13 Nov 2026
- Assigned by
- GitHub_M
- EPSS
- 0.516% likely to be exploited in the next 30 days, higher than 44.497% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: none; Automatable: no; Technical impact: partial
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 6.3CVSS 4.0, Mediumfrom the CNA (GitHub_M)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| aio-libs | aiohttp |
|
Timeline
- 13 Nov 2026 Published
Weakness
References
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-5pv8-vvhc-h7jv
- https://github.com/aio-libs/aiohttp/pull/13930
- https://github.com/aio-libs/aiohttp/pull/13942
- https://github.com/aio-libs/aiohttp/commit/6963ee0befec1502b6bb7b4db6c72d044c08f4fa
- https://github.com/aio-libs/aiohttp/commit/b1f6c87b2bd3bd80f2b6c22ff46e11d00921e412
- https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4