CVE-2026-17358 in API Connect
Summary
by MITRE • 11/07/2026
IBM API Connect 10.0.8.0 through 10.0.8.12 and 12.1.0.0 through 12.1.1.2 could allow a remote authenticated attacker to bypass authentication across tenants due to improper authentication. Authentication checks are not sufficiently isolated between tenants, which could allow a user from one tenant to be accepted by another.
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Analysis
by VulDB Data Team • 11/07/2026
The vulnerability identified in IBM API Connect versions 10.0.8.0 through 10.0.8.12 and 12.1.0.0 through 12.1.1.2 represents a critical failure in multi-tenant security isolation, specifically classified under CWE-306: Missing Authentication for Critical Function. This flaw allows an authenticated attacker operating within one tenant context to bypass authentication mechanisms when interacting with resources belonging to a different tenant. The core technical issue stems from improper handling of session tokens or identity assertions where the validation logic fails to strictly bind the user's credentials and permissions to their specific organizational boundary. Consequently, the system erroneously accepts valid authentication data from Tenant A as sufficient for accessing protected endpoints in Tenant B, effectively nullifying the logical separation that is fundamental to Software-as-a-Service architectures.
From an operational perspective, this vulnerability enables unauthorized lateral movement across tenant boundaries within a shared infrastructure environment. An attacker who has obtained legitimate credentials for one organization can exploit this misconfiguration to access sensitive data, modify configurations, or execute administrative functions on behalf of another organization without needing additional authentication steps. This breach of isolation undermines the trust model inherent in multi-tenant deployments and poses severe risks including data exfiltration, intellectual property theft, and potential regulatory non-compliance for affected organizations. The impact is particularly acute because it requires only a single valid set of credentials from any tenant to compromise others, significantly lowering the barrier for exploitation compared to vulnerabilities requiring privilege escalation or credential stuffing.
This type of vulnerability aligns with MITRE ATT&CK technique T1078: Valid Accounts, specifically within the context of multi-tenant environments where identity boundaries are blurred. It also reflects weaknesses in access control enforcement often categorized under CWE-269: Improper Privilege Management when considering the elevation of scope from one tenant to another. The root cause typically involves a flaw in how session identifiers or JWT tokens are parsed and validated, potentially due to missing checks for tenant ID claims or improper scoping of security contexts during request processing. Such flaws often arise when developers assume that upstream authentication providers correctly isolate sessions, failing to implement defense-in-depth measures at the application layer itself.
To mitigate this risk, organizations running affected versions must immediately apply vendor-provided patches that address the session validation logic and enforce strict tenant isolation checks on all API requests. Security teams should also audit their current deployments for any signs of unauthorized cross-tenant access by reviewing logs for anomalous activity patterns where a single user identity appears to interact with multiple distinct tenants in rapid succession or without expected context switches. Implementing additional monitoring rules that flag unusual data transfer volumes between disparate tenant contexts can provide early detection capabilities while patching efforts are underway. Furthermore, future development processes should incorporate static and dynamic analysis tools specifically configured to detect missing authentication checks across logical boundaries, ensuring that multi-tenant isolation is rigorously tested during the software lifecycle rather than treated as an afterthought.