CVE-2026-67355 guzzlehttp/guzzle before 7.15.1 Host-only Cookie Scope
Attackers controlling child hosts can steal host-only cookies, including session identifiers and tokens, from the parent host's cookie jar.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-67355?
CVE-2026-67355 is a high-severity vulnerability in guzzle, published on 1 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
guzzlehttp/guzzle versions before 7.15.1 fail to preserve host-only cookie scope, storing the request host in the Domain field instead of marking cookies as host-only. Attackers controlling child hosts can receive host-only cookies intended only for parent hosts, potentially disclosing session identifiers and authorization tokens when the same cookie jar is reused across trust boundaries.
Weakness: CWE-201
Which versions are affected by CVE-2026-67355?
2 open source packages ship an affected version, including guzzlehttp/guzzle.
| Package | Affected | Fixed in |
|---|---|---|
guzzlehttp/guzzle Packagist | All versions | 7.15.1 |
guzzlehttp/guzzle Packagist | All versions | 7.15.1 |
How do I fix CVE-2026-67355?
Upgrade guzzlehttp/guzzle to 7.15.1 or later.
Is CVE-2026-67355 being exploited?
There is no known exploitation of CVE-2026-67355 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-67355, GHSA-wm3w-8rrp-j577, MINI-39cp-76w6-73qx, MINI-f559-rh4q-xhp9, MINI-jxr3-w9w3-6729, MINI-m5gr-jwpq-f3h3 and 5 more.