CVE-2026-27591
Privilege Escalation in Winter CMS via Role Modification
Publication date: 2026-03-11
Last updated on: 2026-03-19
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| wintercms | winter | to 1.0.477 (exc) |
| wintercms | winter | From 1.1.0 (inc) to 1.1.12 (exc) |
| wintercms | winter | From 1.2.0 (inc) to 1.2.12 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-284 | The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. |
| CWE-915 | The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified. |
| CWE-639 | The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in Winter CMS, an open-source content management system based on the Laravel PHP framework. Before versions 1.0.477, 1.1.12, and 1.2.12, authenticated backend users could escalate their access level by modifying the roles or permissions assigned to their account. They could do this by sending specially crafted requests to the backend while logged in.
To exploit this vulnerability, an attacker must already have access to the backend with any level of user account. The vulnerability allows them to increase their privileges beyond what was originally assigned.
How can this vulnerability impact me? :
This vulnerability can have a severe impact because it allows an authenticated user to escalate their privileges to a higher access level within the Winter CMS backend.
- An attacker with any backend access can gain full control over the system.
- They can modify roles and permissions, potentially leading to unauthorized data access, data modification, or deletion.
- The vulnerability has a high CVSS score of 9.9, indicating critical severity with high impact on confidentiality, integrity, and availability.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade Winter CMS to version 1.0.477, 1.1.12, or 1.2.12 or later, depending on your installed version series.
Ensure that only trusted users have backend access, as exploitation requires an authenticated backend user account.