Intel

AIKIDO-2026-254447

guzzlehttp/guzzle is vulnerable to Origin Validation Error

Origin Validation ErrorCVE-2026-55767 Published 3 days ago

58

Medium Risk

This Affects:

PHPguzzlehttp/guzzle
1.0.3 - 7.12.0
Fixed in 7.12.1
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TL;DR

A flaw in guzzle's CookieJar allows cookies with dot-only Domain attributes (e.g., Domain=., Domain=.., Domain= . ) to bypass validation — the leading-dot stripping in matchesDomain() normalizes these to an empty string, which validate() fails to reject, causing the cookie to match any request host. Applications sharing a single CookieJar across attacker-controlled and trusted origins are at risk of cookie injection or session fixation against downstream services.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range.

Background info

guzzlehttp/guzzle is vulnerable to Origin Validation Error in versions 1.0.3 - 7.12.0.

How to fix this

Upgrade the guzzlehttp/guzzle library to the patch version.