Guzzle: Host-only cookie scope is not preserved

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

• CVE-2026-67355: 0.37% estimated exploitation activity in the next 30 days; percentile 30.52 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact In affected versions, CookieJar does not preserve whether a response cookie was set without a Domain attribute or with an empty one. A cookie without Domain is host-only and must be returned only to the exact host that set it. Under current cookie processing rules, an empty Domain value is also host-only. Guzzle instead stores the request host in the cookie's Domain field and later applies ordinary domain matching, as though the server had supplied a valid domain. For example, a host-only sid=secret cookie set by example.com can subsequently be sent to child.example.com. FileCookieJar and SessionCookieJar also persist the request host without recording the host-only state, so reloading a jar preserves the widened scope. An attacker who controls or can observe a child host can therefore receive cookies that were intended only for its parent host. Depending on the cookie, this can disclose session identifiers, authorization tokens, or other sensitive state. Exploitation requires…

Published by the source

20 Jul 2026, 23:27 UTC

Last modified by the source

4 Aug 2026, 12:55 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-wm3w-8rrp-j577

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# Patch Next advisory brief: CVE-2026-67355

Advisory: Guzzle: Host-only cookie scope is not preserved
IDs: CVE-2026-67355, GHSA-wm3w-8rrp-j577
Record: https://patchnext.com/advisories/cve-2026-67355 (revision 1, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: guzzlehttp/guzzle 7.15.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist guzzlehttp/guzzle: affected < 7.15.1; fixed in 7.15.1

## Suggested inspection (read-only)
- Packagist guzzlehttp/guzzle: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on guzzlehttp/guzzle.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-wm3w-8rrp-j577 (GitHub-reviewed advisory GHSA-wm3w-8rrp-j577 lists affected ranges: Packagist guzzlehttp/guzzle >=0 <7.15.1)

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