CVE-2026-23922 in Zabbix
Summary
by MITRE • 08/18/2026
The email media OAuth field 'Client secret' cannot be read after saving, but a Super Admin can leak it by setting a malicious 'Token endpoint'. Changes were made to reset the client secret upon changing the token endpoint.
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Analysis
by VulDB Data Team • 08/18/2026
This vulnerability represents a critical authentication and authorization flaw within an application's email media OAuth configuration interface, specifically targeting the handling of sensitive credentials such as Client Secrets. The core issue stems from improper access control mechanisms combined with insecure data management practices during credential rotation or modification processes. While standard users are correctly prevented from viewing the stored Client Secret after it has been saved to prevent accidental exposure, the system fails to adequately restrict administrative actions that can inadvertently or maliciously trigger a disclosure of this sensitive material. This discrepancy in privilege levels creates an attack vector where individuals with Super Admin privileges can exploit specific configuration fields to exfiltrate credentials that should remain confidential even from high-level administrators unless explicitly intended for rotation purposes.
The technical mechanism involves the manipulation of the Token Endpoint field, which is designed to specify the URL used by OAuth clients to obtain access tokens. Under normal operational procedures, changing this endpoint might trigger a security protocol to reset associated secrets to ensure integrity and prevent replay attacks using stale credentials against new endpoints. However, in this flawed implementation, the process for resetting or handling the Client Secret when the Token Endpoint is modified contains a logic error that results in the secret being exposed rather than securely regenerated or masked. A Super Admin can set a malicious Token endpoint value, which triggers the internal reset routine but fails to properly obscure the resulting new Client Secret before it is returned to the user interface or stored in a way that allows retrieval. This effectively bypasses the intended security controls designed to protect sensitive authentication data from administrative users who should not have direct access to plaintext secrets unless undergoing an authorized rotation process under strict audit conditions.
From an industry standard perspective, this vulnerability aligns with CWE-259, Use of Hard-coded Passwords, or more accurately CWE-798: Use of Hard-coded Credentials if the secret is exposed in a way that makes it static and retrievable by unauthorized parties within the admin scope. It also relates to CWE-613: Insufficient Session Expiration, as the exposure allows for potential long-term misuse of compromised credentials. In terms of attack vectors, this falls under MITRE ATT&CK technique T1078: Valid Accounts, specifically involving administrative account abuse. An attacker with Super Admin privileges can leverage their existing access to perform unauthorized credential harvesting without needing to escalate privileges further or exploit external system vulnerabilities. This represents an insider threat scenario where the trust placed in high-level administrators is exploited due to insufficient separation of duties and lack of proper auditing for sensitive configuration changes that involve cryptographic material exposure.
The operational impact of this vulnerability is severe, as Client Secrets are critical components of OAuth 2.0 authentication flows used by email media services to verify client identity. If these secrets are leaked through the described mechanism, attackers can impersonate legitimate applications or services configured with those credentials. This could lead to unauthorized access to user emails, interception of sensitive communications, and potential compromise of downstream systems that trust the compromised OAuth clients. Furthermore, because the exposure occurs via a configuration change rather than a direct database query bypass, it may evade standard intrusion detection systems that monitor for unusual data extraction patterns from databases. The ability to leak secrets through administrative interface manipulation undermines the principle of least privilege and compromises the integrity of the entire authentication infrastructure managed by the platform.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. Immediately, developers should review the code handling Token Endpoint modifications to ensure that any reset operation for Client Secrets does not return the plaintext secret in API responses or UI fields unless explicitly requested through a secure, multi-factor authenticated process designed specifically for credential rotation. Implementing strict logging and alerting for all changes to OAuth configurations involving sensitive fields is essential to detect potential abuse of Super Admin privileges. Additionally, adopting a zero-trust architecture where even administrators must request access to secrets via a privileged identity management system with just-in-time access controls would prevent direct exposure. Regular security audits focusing on privilege escalation paths within administrative interfaces and enforcing separation of duties between configuration management and credential storage systems are critical steps to resolve this vulnerability and restore trust in the application's authentication mechanisms.