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Advisory record · GHSA-gx76-c99x-2c96

AIOHTTP: Cookie from subdomain can remove Host-Only Scope from existing cookies

CVSS 2.3 LowEPSS 0.0038 · 32nd percentile

Published by the GitHub Advisory Database at 20 Oct 2026, 19:58 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
aiohttpPyPI<3.14.43.14.4
Identifiers
GHSA-gx76-c99x-2c96 · CVE-2026-111749
Weakness (CWE)
CWE-565
Tags
Published
20 Oct 2026
Updated
20 Oct 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Versions of aiohttp before 3.14.4 are affected. A subdomain under an untrusted domain can remove the Host-Only flag from an existing cookie set for a parent domain, which strips the Host-Only protection from that cookie. The source says the impact is limited because most use cases do not reflect these cookies back to a browser. Upgrade to aiohttp 3.14.4.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
2.3 Low 4.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0038, the 32nd percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:08 UTC First seen by agentprime
  2. 31 Oct 2026, 14:08 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.