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🐍 PyPI
Not in CISA KEV
HIGH severity

aiohttp: Host-Only Cookies Become Domain Cookies After CookieJar PersistenceGHSA-2fqr-mr3j-6wp8

HIGHFix: aio-libs/aiohttp@a329a7a

GHSA-2fqr-mr3j-6wp8 is a high-severity (CVSS 7.5) CWE-665 vulnerability in aiohttp. A fix is available for aiohttp — see the affected versions and patch details below.

Also known asCVE-2026-54279PYSEC-2026-2112
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 10, 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 GHSA-2fqr-mr3j-6wp8.

EPSS Exploitation Probability

via FIRST.org ↗
0.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs43th percentile — riskier than 43% of all scored CVEsHighest risk
0.00%0.33%0.66%0.99%0.3%0.5%Jul 26Oct 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

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

Summary

Host-only cookies that are saved with CookieJar.save() and then restored later with CookieJar.load() lose their host-only status.

Impact

Host-only cookies that have been loaded from disk may get sent to subdomains that previously should have been disallowed.

Patch: https://github.com/aio-libs/aiohttp/commit/a329a7aacad5284f087af36103aff778746da0f2

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIaiohttpall versions3.14.1pip install --upgrade 'aiohttp==3.14.1'

Affected Products

1 product · 1 configurations
Application
aiohttpaiohttp
< 3.14.1
range

Detection & mitigation playbook

Open-source dependency

  1. 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.

  2. Fix

    Update aiohttp to 3.14.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2fqr-mr3j-6wp8 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Summary Host-only cookies that are saved with ``CookieJar.save()`` and then restored later with ``CookieJar.load()`` lose their host-only status. ### Impact Host-only cookies that have been loaded from disk may get sent to subdomains that previously should have been disallowed. ----- Patch: https://github.com/aio-libs/aiohttp/commit/a329a7aacad5284f087af36103aff778746da0f2
O3 Security · Impact-Aware SCA

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aiohttp: Host-Only Cookies Become Domain Cookies…