Guzzle: Cookie Disclosure and Injection via IP-Address Domains

Exploitation

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

CVSS

4.7 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

• CVE-2026-59883: 0.17% estimated exploitation activity in the next 30 days; percentile 6.03 (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 CookieJar does not restrict a cookie scoped to an IP address to the exact host that set it. When a stored cookie's Domain attribute is an IPv4 literal (Domain=192.168.0.1), a bracketed IPv6 literal (Domain=[::1]), or a bare numeric value that denotes an IPv4 address (Domain=1, which is 0.0.0.1), SetCookie::matchesDomain() applies ordinary subdomain (suffix) matching to it instead of requiring an exact host. The IP-address check inside matchesDomain() is applied only to the request host and never to the cookie's own domain, and response cookies that carry an explicit Domain attribute are stored as suffix-matchable. As a result Guzzle sends such a cookie to any host whose name ends in that value as a trailing label, for example sending a Domain=192.168.0.1 cookie to evil.192.168.0.1, or a Domain=1 cookie to evil.1. The same flaw lets a look-alike host store a cookie that Guzzle then sends to the bare IP address. Depending on how the receiving service interprets the cookie, the…

Published by the source

20 Jul 2026, 22:00 UTC

Last modified by the source

20 Jul 2026, 22:00 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-g446-98w2-8p5w

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# Patch Next advisory brief: CVE-2026-59883

Advisory: Guzzle: Cookie Disclosure and Injection via IP-Address Domains
IDs: CVE-2026-59883, GHSA-g446-98w2-8p5w
Record: https://patchnext.com/advisories/cve-2026-59883 (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 4.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: guzzlehttp/guzzle 7.12.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist guzzlehttp/guzzle: affected < 7.12.3; fixed in 7.12.3

## 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-g446-98w2-8p5w (GitHub-reviewed advisory GHSA-g446-98w2-8p5w lists affected ranges: Packagist guzzlehttp/guzzle >=0 <7.12.3)

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