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CVE-2026-128125 AIOHTTP: Unbounded cookie storage in client CookieJar

6.3 medium

Medium (6.3) in aio-libs aiohttp.

On this page
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.

Severity

CVSS 4.0

6.3 medium
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
CISA's assessment (SSVC)
Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-13. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
CWE
CWE-1325 Improperly Controlled Sequential Memory Allocation
Published
Modified
Assigned by
GitHub_M (CNA)
NVD analysis
Awaiting analysis
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
aio-libs aiohttp< 3.14.4

Attack patterns (CAPEC)

  • CAPEC-130 Excessive Allocation Likelihood: Medium · Severity: Medium

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

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