GHSA-PGPF-M8M4-6CG6
Vulnerability from github – Published: 2026-03-12 14:07 – Updated: 2026-03-12 14:07Impact
Affected 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.
To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access.
The 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).
Patches
Multiple fixes and defence in depth has been applied to prevent current and future privilege escalation attacks at the lowest level possible.
This 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.
Workarounds
If you cannot upgrade, you may apply the changes from the releases to your Winter CMS installation manually to resolve this issue.
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "winter/wn-backend-module"
},
"ranges": [
{
"events": [
{
"introduced": "1.2.0"
},
{
"fixed": "1.2.12"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "winter/wn-backend-module"
},
"ranges": [
{
"events": [
{
"introduced": "1.1.0"
},
{
"fixed": "1.1.12"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "winter/wn-backend-module"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.0.477"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-27591"
],
"database_specific": {
"cwe_ids": [
"CWE-284",
"CWE-639",
"CWE-915"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-12T14:07:39Z",
"nvd_published_at": "2026-03-11T22:16:32Z",
"severity": "CRITICAL"
},
"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 \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.",
"id": "GHSA-pgpf-m8m4-6cg6",
"modified": "2026-03-12T14:07:39Z",
"published": "2026-03-12T14:07:39Z",
"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"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Winter vulnerable to privilege escalation by authenticated backend users"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.