CVE-2026-27899

Privilege Escalation to Admin via User Self-Update in wg-portal

Any authenticated non-admin user can become a full administrator by sending a single PUT request to their own user profile endpoint with "IsAdmin": true in the JSON body. After logging out and back in, the session picks up admin privileges from the database.

Tested against wg-portal v2.1.2 (Docker image wgportal/wg-portal:v2).

Root Cause

When a user updates their own profile, the server parses the full JSON body into the user model, including the IsAdmin boolean field. A function responsible for preserving calculated or protected attributes pins certain fields to their database values (such as base model data, linked peer count, and authentication data), but it does not do this for IsAdmin. As a result, whatever value the client sends for IsAdmin is written directly to the database.

After the exploit, the attacker has full admin access to the WireGuard VPN management portal. They can:

• Read and modify every user account
• Create, modify, and delete WireGuard peers on any interface
• View WireGuard interface configurations
• Disable or lock other user accounts
• Access the full user list and their API tokens

The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access. Typical impact: privilege escalation beyond the intended level.

CVE-2026-27899 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.1.3); upgrading removes the vulnerable code path.

Kodem intelligence

The problem was fixed in the latest release, v2.1.3. The docker images for the tag 'latest' built from the master branch also include the fix.

1. What is CVE-2026-27899? CVE-2026-27899 is a high-severity improper privilege management vulnerability in github.com/h44z/wg-portal (go), affecting versions <= 2.1.2. It is fixed in 2.1.3. The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access.
2. How severe is CVE-2026-27899? CVE-2026-27899 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/h44z/wg-portal are affected by CVE-2026-27899? github.com/h44z/wg-portal (go) versions <= 2.1.2 is affected.
4. Is there a fix for CVE-2026-27899? Yes. CVE-2026-27899 is fixed in 2.1.3. Upgrade to this version or later.
5. Is CVE-2026-27899 exploitable, and should I be worried? Whether CVE-2026-27899 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-27899 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-27899? Upgrade github.com/h44z/wg-portal to 2.1.3 or later.