CVE-2026-59883: Guzzlephp Guzzle

Medium severity, CVSS 6.1. EPSS: 0.2% chance of exploitation in the next 30 days.

Guzzle is an extensible PHP HTTP client. Prior to 7.12.3, CookieJar did not restrict cookies scoped to IP-address or bare-numeric Domain values to the exact host that set them, because SetCookie::matchesDomain() applied ordinary suffix matching to domains such as 192.168.0.1, [::1], or 1, allowing cross-host cookie disclosure, cookie injection, or session fixation. This issue is fixed in version 7.12.3.

Affected products

• Guzzlephp Guzzle: before 7.12.3 (fixed in 7.12.3)

Published 2026-07-08. Last modified 2026-07-13.