CVE-2026-55767

Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, CookieJar incorrectly accepts cookies with a dot-only Domain attribute and whitespace-padded variants. SetCookie::matchesDomain() removes leading dots from the cookie domain, normalizing dot-only values to the empty string; SetCookie::validate() only rejected a strictly empty domain, so these cookies could be stored and the empty normalized domain was treated as matching any request host. An attacker-controlled origin that an application requests with a shared cookie jar can therefore set a cookie that Guzzle later sends to unrelated hosts using the same jar. This may allow cookie injection or session fixation against downstream services, depending on how those services interpret the injected cookie. This vulnerability is fixed in 7.12.1.

CVSS v3 5.8 MEDIUM

5.8^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://github.com/guzzle/guzzle/security/advisories/GHSA-cwxw-98qj-8qjx	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:guzzlephp:guzzle:*:*:*:*:*:*:*:*

History

26 Jun 2026, 19:34

Type	Values Removed	Values Added
References	~~() https://github.com/guzzle/guzzle/security/advisories/GHSA-cwxw-98qj-8qjx -~~	() https://github.com/guzzle/guzzle/security/advisories/GHSA-cwxw-98qj-8qjx - Third Party Advisory
CPE		cpe:2.3:a:guzzlephp:guzzle::::::::
First Time		Guzzlephp guzzle Guzzlephp

23 Jun 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-23 16:17

Updated : 2026-06-26 19:34

NVD link : CVE-2026-55767

Mitre link : CVE-2026-55767

CVE.ORG link : CVE-2026-55767

JSON object : View

Products Affected

guzzlephp

guzzle

CWE

CWE-346

Origin Validation Error

CWE-1286

Improper Validation of Syntactic Correctness of Input

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