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Response snapshot Nov 3, 2026, 19:21 UTC

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VulnerabilityCVE-2026-54279

aiohttp: Host-Only Cookies Become Domain Cookies After CookieJar Persistence

Host-only cookies that are saved with CookieJar.save() and then restored later with CookieJar.load() lose their host-only status. Host-only cookies that have been loaded from disk may get sent to subdomains that previously should have been disallowed. ----- Patch: https://github.

At a glance

Exploited
Not known
Severity
1.3 Low (CVSS 4.0)
Chance of exploitation
0.5% in the next 30 days
Sources
1 source

What to do

GitHub lists first patched versions: aiohttp: 3.14.1. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-2fqr-mr3j-6wp8 (opens a new tab)

What happened

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.

Continue reading

-----

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

Affected package ranges reported by GitHub: aiohttp: <= 3.14.0

Scores and how they were measured

CVSS base severity

1.3

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N/E:U

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.5%

Scored Percentile 42.4%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-2fqr-mr3j-6wp8 (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-2fqr-mr3j-6wp8, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  3. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-54279, scored 2026-11-03. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 3). aiohttp: Host-Only Cookies Become Domain Cookies After CookieJar Persistence (CVE-2026-54279). https://kevwire.com/record/CVE-2026-54279

MLA

"aiohttp: Host-Only Cookies Become Domain Cookies After CookieJar Persistence (CVE-2026-54279)." KEVWire, 3 Nov. 2026, kevwire.com/record/CVE-2026-54279.

Chicago

KEVWire. "aiohttp: Host-Only Cookies Become Domain Cookies After CookieJar Persistence (CVE-2026-54279)." Last modified November 3, 2026. https://kevwire.com/record/CVE-2026-54279.

Evidence summary (plain text)

aiohttp: Host-Only Cookies Become Domain Cookies After CookieJar Persistence (Jun 15, 2026).
Host-only cookies that are saved with CookieJar.save() and then restored later with CookieJar.load() lose their host-only status.

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
CVSS 1.3 (version 4.0; evidence as of Nov 3, 2026; https://github.com/advisories/GHSA-2fqr-mr3j-6wp8).
EPSS 0.5% for the following 30 days, scored Nov 3, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-54279&date=2026-11-03).
Sources:
GitHub-reviewed advisory GHSA-2fqr-mr3j-6wp8: https://github.com/advisories/GHSA-2fqr-mr3j-6wp8
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-54279&date=2026-11-03
Record ID: CVE-2026-54279.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 3, 2026, 17:36 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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