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GHSA-pgpf-m8m4-6cg6
GHSA-r39q-jr8h-gcq2

Author: advisory-database[bot]

advisories/github-reviewed/2026/03/GHSA-pgpf-m8m4-6cg6/GHSA-pgpf-m8m4-6cg6.json

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+{
+  "schema_version": "1.4.0",
+  "id": "GHSA-pgpf-m8m4-6cg6",
+  "modified": "2026-03-12T14:07:39Z",
+  "published": "2026-03-12T14:07:39Z",
+  "aliases": [
+    "CVE-2026-27591"
+  ],
+  "summary": "Winter vulnerable to privilege escalation by authenticated backend users",
+  "details": "## 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 & 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.",
+  "severity": [
+    {
+      "type": "CVSS_V3",
+      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
+    }
+  ],
+  "affected": [
+    {
+      "package": {
+        "ecosystem": "Packagist",
+        "name": "winter/wn-backend-module"
+      },
+      "ranges": [
+        {
+          "type": "ECOSYSTEM",
+          "events": [
+            {
+              "introduced": "1.2.0"
+            },
+            {
+              "fixed": "1.2.12"
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "package": {
+        "ecosystem": "Packagist",
+        "name": "winter/wn-backend-module"
+      },
+      "ranges": [
+        {
+          "type": "ECOSYSTEM",
+          "events": [
+            {
+              "introduced": "1.1.0"
+            },
+            {
+              "fixed": "1.1.12"
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "package": {
+        "ecosystem": "Packagist",
+        "name": "winter/wn-backend-module"
+      },
+      "ranges": [
+        {
+          "type": "ECOSYSTEM",
+          "events": [
+            {
+              "introduced": "0"
+            },
+            {
+              "fixed": "1.0.477"
+            }
+          ]
+        }
+      ]
+    }
+  ],
+  "references": [
+    {
+      "type": "WEB",
+      "url": "https://github.com/wintercms/winter/security/advisories/GHSA-pgpf-m8m4-6cg6"
+    },
+    {
+      "type": "ADVISORY",
+      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27591"
+    },
+    {
+      "type": "PACKAGE",
+      "url": "https://github.com/wintercms/winter"
+    },
+    {
+      "type": "WEB",
+      "url": "https://wintercms.com/releases/v1.0.477"
+    },
+    {
+      "type": "WEB",
+      "url": "https://wintercms.com/releases/v1.1.12"
+    },
+    {
+      "type": "WEB",
+      "url": "https://wintercms.com/releases/v1.2.12"
+    }
+  ],
+  "database_specific": {
+    "cwe_ids": [
+      "CWE-284",
+      "CWE-639",
+      "CWE-915"
+    ],
+    "severity": "CRITICAL",
+    "github_reviewed": true,
+    "github_reviewed_at": "2026-03-12T14:07:39Z",
+    "nvd_published_at": "2026-03-11T22:16:32Z"
+  }
+}