{"id":"CVE-2026-27591","aliases":["EUVD-2026-11406","GHSA-pgpf-m8m4-6cg6"],"status":"published","title":"Winter: Privilege escalation by authenticated backend users","description":"Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.0.477, 1.1.12, and 1.2.12, Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in. To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access. This vulnerability is fixed in 1.0.477, 1.1.12, and 1.2.12.","severity":{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00777,"percentile":0.56114,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-284","CWE-639","CWE-915"],"published":"2026-03-11T21:25:35Z","modified":"2026-10-28T02:31:09Z","fixes":[{"ecosystem":"Packagist","package":"winter/wn-backend-module","fixed_in":["1.2.12","1.1.12","1.0.477"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"winter/wn-backend-module","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.2.0"},{"fixed":"1.2.12"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"winter/wn-backend-module","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.1.0"},{"fixed":"1.1.12"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"winter/wn-backend-module","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.477"}]}]},{"source":"osv","ecosystem":"Packagist","package":"winter/wn-backend-module","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.2.0"},{"fixed":"1.2.12"}]}],"versions":["v1.2.0","v1.2.1","v1.2.10","v1.2.11","v1.2.2","v1.2.3","v1.2.4","v1.2.5","v1.2.6","v1.2.7","v1.2.8","v1.2.9"]},{"source":"osv","ecosystem":"Packagist","package":"winter/wn-backend-module","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.1.0"},{"fixed":"1.1.12"}]}],"versions":["v1.1.10","v1.1.11","v1.1.2","v1.1.3","v1.1.4","v1.1.5","v1.1.6","v1.1.7","v1.1.8","v1.1.9"]},{"source":"osv","ecosystem":"Packagist","package":"winter/wn-backend-module","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.477"}]}],"versions":["v1.0.473","v1.0.474","v1.0.475"]}],"products":[{"vendor":"wintercms","product":"winter"}],"references":[{"url":"https://github.com/wintercms/winter/security/advisories/GHSA-pgpf-m8m4-6cg6","tags":["x_refsource_CONFIRM","Patch","Vendor Advisory","advisory","web"]},{"url":"https://wintercms.com/releases/v1.0.477","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://wintercms.com/releases/v1.1.12","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://wintercms.com/releases/v1.2.12","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27591","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-pgpf-m8m4-6cg6"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27591.json","tags":["advisory"]},{"url":"https://github.com/wintercms/winter","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-27591","title":"Winter: Privilege escalation by authenticated backend users","description":"Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.0.477, 1.1.12, and 1.2.12, Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in. To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access. This vulnerability is fixed in 1.0.477, 1.1.12, and 1.2.12.","status":"published","published":"2026-03-11T21:25:35.289Z","modified":"2026-03-12T14:23:06.447Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna"}],"cwes":["CWE-284","CWE-639","CWE-915"],"updated_at":"2026-11-02T14:19:49.199185Z"}],"euvd":[{"id":"EUVD-2026-11406","description":"Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.0.477, 1.1.12, and 1.2.12, Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in. To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access. This vulnerability is fixed in 1.0.477, 1.1.12, and 1.2.12.","status":"published","published":"2026-03-11T21:25:35Z","modified":"2026-03-12T14:23:06Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T19:25:36.272941Z"}],"ghsa":[{"id":"GHSA-pgpf-m8m4-6cg6","title":"Winter vulnerable to privilege escalation by authenticated backend users","description":"## Impact\nAffected versions of Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in.\n\nTo actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access.\n\nThe Winter CMS maintainers strongly recommend that all Winter CMS sites that have any reliance on the roles \u0026 permissions system to update immediately. Security fixes have been backported to all major versions of Winter (1.0, 1.1, and 1.2).\n\n## Patches\nMultiple fixes and defence in depth has been applied to prevent current and future privilege escalation attacks at the lowest level possible.\n\nThis security issue has been fixed as of https://wintercms.com/releases/v1.0.477, https://wintercms.com/releases/v1.1.12, https://wintercms.com/releases/v1.2.12.\n\n## Workarounds\nIf you cannot upgrade, you may apply the changes from the releases to your Winter CMS installation manually to resolve this issue.","status":"published","published":"2026-03-12T14:07:39Z","modified":"2026-03-12T14:07:39Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-284","CWE-639","CWE-915"],"updated_at":"2026-11-02T14:39:34.616253Z"}],"nvd":[{"id":"CVE-2026-27591","description":"Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.0.477, 1.1.12, and 1.2.12, Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in. To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access. This vulnerability is fixed in 1.0.477, 1.1.12, and 1.2.12.","status":"published","published":"2026-03-11T22:16:32.29Z","modified":"2026-06-17T10:27:21.463Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"secondary"}],"cwes":["CWE-284","CWE-639","CWE-915"],"updated_at":"2026-11-02T14:12:08.98071Z"}],"osv":[{"id":"CVE-2026-27591","title":"Winter: Privilege escalation by authenticated backend users","description":"Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.0.477, 1.1.12, and 1.2.12, Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in. To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access. This vulnerability is fixed in 1.0.477, 1.1.12, and 1.2.12.","status":"published","published":"2026-03-11T21:25:35.289Z","modified":"2026-10-28T02:31:09.736834161Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-284","CWE-639","CWE-915"],"updated_at":"2026-11-02T15:45:00.180685Z"},{"id":"GHSA-pgpf-m8m4-6cg6","title":"Winter vulnerable to privilege escalation by authenticated backend users","description":"## Impact\nAffected versions of Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in.\n\nTo actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access.\n\nThe Winter CMS maintainers strongly recommend that all Winter CMS sites that have any reliance on the roles \u0026 permissions system to update immediately. Security fixes have been backported to all major versions of Winter (1.0, 1.1, and 1.2).\n\n## Patches\nMultiple fixes and defence in depth has been applied to prevent current and future privilege escalation attacks at the lowest level possible.\n\nThis security issue has been fixed as of https://wintercms.com/releases/v1.0.477, https://wintercms.com/releases/v1.1.12, https://wintercms.com/releases/v1.2.12.\n\n## Workarounds\nIf you cannot upgrade, you may apply the changes from the releases to your Winter CMS installation manually to resolve this issue.","status":"published","published":"2026-03-12T14:07:39Z","modified":"2026-03-14T02:26:20.72829Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-284","CWE-639","CWE-915"],"updated_at":"2026-11-02T15:46:53.244788Z"}]}}