What is CVE-2026-55767?

CVE-2026-55767 is a medium-severity vulnerability in Guzzle, classified under Origin Validation Error. CVSS score: 5.8/10. Published 2026-06-23.

How severe is CVE-2026-55767?

Medium severity. CVSS v3 base score is 5.8 out of 10.

Vulnerability in Guzzle

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, normal…

CVSS v3 metric

CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N.

Affected products

Guzzle — versions < 7.12.1

Weakness classification (CWE)

CWE-346 — Origin Validation Error
CWE-1286

References

security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-55767?: CVE-2026-55767 is a medium-severity vulnerability in Guzzle, classified under Origin Validation Error. CVSS score: 5.8/10. Published 2026-06-23.
How severe is CVE-2026-55767?: Medium severity. CVSS v3 base score is 5.8 out of 10.