CVE-2026-29002
Privilege Escalation in CouchCMS via f_k_levels_list Parameter Tampering
Publication date: 2026-04-10
Last updated on: 2026-04-16
Assigner: VulnCheck
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| couchcms | couchcms | to 2.4 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| 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
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
This vulnerability allows an authenticated Admin user to escalate privileges to SuperAdmin by bypassing authorization controls, resulting in full application control. Such unauthorized privilege escalation can lead to unauthorized access, modification, or deletion of sensitive data.
Because the vulnerability impacts confidentiality, integrity, and availability of data within CouchCMS, it can negatively affect compliance with data protection standards and regulations such as GDPR and HIPAA, which require strict access controls and protection of sensitive information.
Organizations using CouchCMS without mitigating this vulnerability may face increased risk of data breaches or unauthorized data manipulation, potentially leading to non-compliance with these regulations.
Can you explain this vulnerability to me?
CVE-2026-29002 is a privilege escalation vulnerability in CouchCMS that allows authenticated Admin-level users to create SuperAdmin accounts by tampering with the f_k_levels_list parameter in user creation HTTP requests.
Normally, the application restricts the creation of SuperAdmin accounts to prevent unauthorized privilege escalation. However, by modifying the f_k_levels_list parameter value from 4 (normal Admin) to 10 (SuperAdmin) in the HTTP request body, an attacker can bypass these restrictions and gain full application control.
This vulnerability arises due to improper authorization validation and is classified under CWE-639 (Authorization Bypass Through User-Controlled Key).
How can this vulnerability impact me? :
This vulnerability allows an authenticated Admin user to escalate their privileges to SuperAdmin by manipulating the user creation request.
- By creating SuperAdmin accounts, attackers gain full control over the CouchCMS application.
- This full control includes the ability to modify, delete, or access any data within the application.
- It compromises the security model of the application, potentially leading to data breaches, unauthorized changes, and disruption of service.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by monitoring HTTP requests related to user creation in CouchCMS. Specifically, look for requests where the parameter `f_k_levels_list` is set to a value of 10, which indicates an attempt to create a SuperAdmin account by tampering.
To detect exploitation attempts, you can capture and inspect HTTP traffic using tools like Burp Suite or network packet analyzers such as Wireshark.
Example commands or approaches include:
- Use a network packet capture tool (e.g., tcpdump) to capture HTTP POST requests to the user creation endpoint:
- tcpdump -i <interface> -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep 'f_k_levels_list=10'
- Alternatively, use a web application firewall (WAF) or intrusion detection system (IDS) to alert on HTTP requests containing `f_k_levels_list=10` in the request body.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps include:
- Restrict Admin-level user permissions to prevent unauthorized creation or modification of user roles.
- Implement input validation and authorization checks on the server side to ensure the `f_k_levels_list` parameter cannot be tampered with to escalate privileges.
- Monitor and audit user creation requests for suspicious parameter values, especially `f_k_levels_list=10`.
- Apply any available patches or updates from CouchCMS that address this vulnerability.
- If patching is not immediately possible, consider temporarily disabling Admin-level user creation or restricting access to trusted personnel only.