CVE-2026-17274 in IBM
Summary
by MITRE • 09/04/2026
IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to bypass security restrictions due to predictable server seeds.
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Analysis
by VulDB Data Team • 09/04/2026
The vulnerability identified in IBM i operating system versions 7.6, 7.5, 7.4, and 7.3 stems from the use of predictable pseudo-random number generators for generating cryptographic keys or session tokens during authentication processes. In secure systems, randomness is critical to ensure that generated secrets are unique and unpredictable, thereby preventing attackers from guessing valid credentials or session identifiers. When a system relies on deterministic algorithms with insufficient entropy sources, such as using server seeds derived from static values or easily guessable inputs like timestamps without sufficient mixing, the resulting outputs become susceptible to prediction. This flaw effectively undermines the core security principle of unpredictability required for robust authentication mechanisms and key exchange protocols within the IBM i environment.
From a technical perspective, this issue represents a failure in proper entropy collection during the initialization of cryptographic primitives or session management modules. The server seed, which serves as an input to random number generation functions, lacks sufficient variability due to predictable patterns in its derivation process. An attacker who has already authenticated to the system can exploit this weakness by analyzing previous outputs or leveraging knowledge of the underlying algorithmic structure to forecast future seeds. This capability allows the adversary to generate valid authentication tokens or cryptographic keys that are indistinguishable from those legitimately issued by the server, effectively bypassing access controls designed to restrict unauthorized operations.
The operational impact of this vulnerability is severe for any organization relying on IBM i systems for critical business functions. A remote authenticated attacker can leverage predictable seeds to impersonate legitimate users, escalate privileges, or intercept sensitive data transmissions that depend on secure session management. This compromise erodes trust in the integrity of authentication workflows and may lead to unauthorized access to confidential databases, financial records, or proprietary intellectual property stored within the IBM i environment. Furthermore, because the attacker must first authenticate, this vulnerability often serves as a stepping stone for lateral movement within a network if initial credentials are obtained through phishing or other means, amplifying the potential scope of damage beyond isolated system compromises.
This flaw aligns with Common Weakness Enumeration (CWE) category CWE-330, which describes the use of insufficiently random values in cryptographic contexts, and is closely related to CWE-142 regarding predictable algorithms for generating keys or tokens. In terms of adversary tactics, this vulnerability supports techniques associated with MITRE ATT&CK subcategory T1588, specifically obtaining credentials through exploitation of weak randomness mechanisms rather than direct cracking. It also facilitates privilege escalation scenarios where session hijacking becomes feasible due to the predictability of session identifiers.
To mitigate these risks, organizations should immediately apply vendor-provided security patches that address the entropy generation flaws within the affected IBM i versions. Administrators must ensure that all systems are updated to the latest cumulative fix levels released by IBM for their respective version streams. Additionally, implementing network segmentation can limit the exposure of vulnerable services to only necessary trusted subnets while patching efforts proceed. Regular audits of authentication logs should be conducted to detect anomalies indicative of token prediction attacks, such as repeated login attempts from single sources using seemingly valid but rapidly rotating credentials. Long-term remediation strategies should include reviewing all cryptographic implementations across the infrastructure to ensure compliance with modern standards for randomness generation and key management practices outlined by NIST guidelines.