CVE-2026-85391 in Peppermint
Summary
by MITRE • 09/03/2026
Peppermint through 0.5.5 contains a hardcoded JWT signing secret in docker-compose.yml that allows unauthenticated attackers to forge session tokens for any account. Attackers can use the published secret to mint valid tokens for arbitrary user IDs and access protected endpoints without credentials.
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Analysis
by VulDB Data Team • 09/03/2026
The vulnerability identified in Peppermint versions through 0.5.5 represents a critical failure in application security design, specifically concerning the management of cryptographic keys within containerized deployment configurations. The core technical flaw lies in the inclusion of a hardcoded JSON Web Token signing secret directly inside the docker-compose.yml file used for orchestration and service definition. In secure software architecture, secrets such as JWT signing keys must be treated as sensitive credentials that are distinct from application code or configuration files intended to define infrastructure topology. By embedding this static key within the compose file, which is often committed to version control systems like Git, the organization inadvertently exposes its primary mechanism for authenticating user sessions to anyone with read access to the repository or the deployed container environment. This practice violates fundamental security principles regarding secret management and configuration hygiene, creating a single point of failure that compromises the integrity of the entire authentication subsystem.
From an operational perspective, this misconfiguration allows unauthenticated attackers to forge valid session tokens for any user account within the system. Because JWTs are self-contained stateless tokens, possessing the signing key enables an adversary to generate new tokens with arbitrary claims, including administrative privileges or access to specific user identities, without needing to know the actual passwords of those accounts. This capability effectively bypasses all authentication controls implemented by the application layer. An attacker can craft a token that asserts they are any valid user ID, sign it using the leaked secret, and present it to protected endpoints. The server will validate the signature against the known public or shared key, accept the token as legitimate, and grant access based on the forged claims. This leads directly to unauthorized data exposure, privilege escalation, and potential full system compromise depending on the privileges of the targeted accounts.
This vulnerability aligns with CWE-798: Use of Hard-coded Credentials, which categorizes the use of static passwords or keys in source code as a severe risk factor due to their permanence and ease of discovery. Furthermore, it relates closely to CWE-215: Information Exposure Through Debugging Code if the secret was left in place during development but not removed before production deployment. In terms of offensive security frameworks, this flaw facilitates techniques described under MITRE ATT&CK T1078: Valid Accounts and specifically supports credential manipulation or token forgery tactics that allow adversaries to maintain persistence and move laterally within a network without triggering standard authentication failure alerts. The lack of dynamic secret rotation mechanisms exacerbates the risk, as the compromised key remains valid until manually rotated, which may take considerable time depending on operational procedures.
To mitigate this vulnerability, immediate remediation requires removing the hardcoded JWT signing secret from the docker-compose.yml file and any other source code repositories. Instead, secrets should be injected into the container environment at runtime using secure mechanisms provided by orchestration platforms or dedicated secret management services such as HashiCorp Vault, AWS Secrets Manager, or Azure Key Vault. These tools ensure that sensitive data is encrypted at rest, accessed only by authorized processes via short-lived credentials, and rotated regularly to limit the window of exposure in case of a leak. Additionally, organizations should implement pre-commit hooks or static analysis security testing (SAST) pipelines configured with rulesets like Semgrep or GitLeaks to detect hardcoded secrets before they are committed to version control systems. Regular audits of configuration files for sensitive data patterns and enforcing strict access controls on repository permissions are also essential steps in preventing similar misconfigurations in the future.