{"cve":"CVE-2026-55767","nvd":{"published":"2026-06-23T16:17:03.263","modified":"2026-08-05T22:17:07.543","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","score":5.8},"cwes":["CWE-346","CWE-1286"],"references":["https://github.com/FriendsOfPHP/security-advisories/blob/master/guzzlehttp/guzzle/CVE-2026-55767.yaml","https://github.com/guzzle/guzzle/commit/7f537cded1912349abf5081258d6db19106d774d","https://github.com/guzzle/guzzle/pull/3653","https://github.com/guzzle/guzzle/releases/tag/7.12.1","https://github.com/guzzle/guzzle/security/advisories/GHSA-cwxw-98qj-8qjx"],"products":["guzzlephp:guzzle"],"source":"nvd","synced_at":"2026-10-19T22:39:28.638635428+00:00"},"epss":{"cve":"CVE-2026-55767","score":0.00211,"percentile":0.11424,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-cwxw-98qj-8qjx","url":"https://osv.dev/vulnerability/GHSA-cwxw-98qj-8qjx","summary":"guzzlehttp/guzzle: Dot-Only Cookie Domains Match All Hosts","modified":"2026-09-10T03:50:49.287156552Z","packages":[{"ecosystem":"Packagist","name":"guzzlehttp/guzzle","purl":"pkg:composer/guzzlehttp/guzzle","ranges":["<7.12.1"],"fixed":["7.12.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}