Bug 2498137 (CVE-2026-59883)

Summary: CVE-2026-59883 guzzle/guzzle: Guzzle: Cross-host cookie disclosure and injection due to improper domain matching in CookieJar.
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Guzzle, an extensible PHP HTTP client. The CookieJar component improperly handled cookies for IP-address or bare-numeric domains, failing to restrict them to the exact host. This vulnerability could allow a remote attacker to disclose cookies across different hosts, inject malicious cookies, or fixate user sessions, potentially leading to unauthorized access or session hijacking.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-07-08 17:01:24 UTC
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.