Key points
- The flaw affects Gravitee API Management versions up to and including 4.12.22.
- Attackers exploit a shipped default jwt.secret to sign HS256 tokens.
- The vulnerability allows full impersonation of any user, including administrators.
The short version
- A critical authentication bypass exists in Gravitee API Management through version 4.12.22.
- Remote attackers can forge JSON Web Tokens without needing valid credentials.
- Successful exploitation grants the attacker complete administrative control over the API platform.
The details
Gravitee API Management contains a severe authentication bypass vulnerability in all versions released up to 4.12.22. The flaw stems from the use of a default secret key, specifically the jwt.secret, which is shipped with the software. According to the National Vulnerability Database, this configuration allows unauthenticated remote attackers to impersonate any user on the system.
An attacker who knows an existing user ID can craft a JSON Web Token using the HS256 algorithm. By signing this token with the known default secret, the attacker creates a valid bearer token. Presenting this forged token to the Management API allows the attacker to assume the identity of the target user.
If the attacker targets an administrator account ID, they gain full platform control. The vulnerability is classified as critical by the NVD, with a CVSS score of 9.2. It falls under CWE-1394, which relates to the use of a default secret key for data integrity.
The context
This issue highlights the risks of relying on default cryptographic secrets in API management tools. The flaw allows complete bypass of authentication mechanisms, meaning no valid login credentials are required for an attacker to act as an admin.
As TechSec Headlines reported on 2026-10-12, similar authentication bypass flaws in AhsayCBS were actively exploited to deploy webshells and cryptocurrency miners. While that incident involved command injection, the Gravitee flaw demonstrates how default secrets can lead to total platform compromise without additional exploitation steps.
What to watch
Organisations should monitor for unauthorized administrative changes in their API management consoles. Look for new API definitions, modified routing rules, or added user accounts that were not created by internal staff.
Check access logs for bearer tokens that do not match expected authentication patterns. Since the flaw allows impersonation of any known user ID, activity appearing to come from legitimate admin accounts but originating from unusual IP addresses or times should be investigated.
What it means for organisations
Teams usually need to verify if their API gateways are still using factory-default cryptographic keys. Security leaders should ask whether automated deployment scripts reset these secrets during installation. Operations managers must determine if external suppliers have access to the API management interface. Internal audit teams should review who has administrative privileges and whether those accounts show signs of unauthorized access. Communication should reach infrastructure owners and vendor risk managers immediately.
What to do and how to stay safe: Gravitee
- Inventory all instances of Gravitee API Management and verify their version numbers against the affected range.
- Check configuration files to see if the jwt.secret remains at its default shipped value.
- Rotate any default secrets immediately and enforce strong, unique cryptographic keys for token signing.
- Review administrative logs for signs of unauthorized access or configuration changes made by impersonated accounts.
Step-by-step guide: Automatic Software Updates: Definition, Mechanics and Hidden Risks
General security guidance from the TechSec Headlines newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
Which versions of Gravitee API Management are affected by this vulnerability?
All versions of Gravitee API Management up to and including 4.12.22 are affected.
What is the CVSS score for this authentication bypass?
The NVD rates the vulnerability as critical with a CVSS score of 9.2.
How can an attacker exploit this flaw?
Attackers can forge HS256 JWTs using the default jwt.secret to impersonate users via the Management API.
