Is CVE-2026-59883 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-59883?

CVE-2026-59883 has a CVSS v3 severity of MEDIUM (4.7).

Back

CVE-2026-59883

Description

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.