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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-55767

26
FAUCET Score

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.

First published: Jun 23, 2026Last modified: Jun 23, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 7.12.1CPE matchmatch criteria
cpe:2.3:a:guzzlephp:guzzle:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.8MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.11%
Probability of exploitation in next 30 days
EPSS Percentile
1.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0011 is in the 0th percentile among its peer group of 23,705 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

composerpatch availablevia ghsa
Product: guzzlehttp/guzzleFixed in: 7.12.1

Vendor Advisories (1)

composerGHSA-cwxw-98qj-8qjxmedium

guzzlehttp/guzzle: Dot-Only Cookie Domains Match All Hosts

Jun 19, 2026

References

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