CVE-2026-18715 in IBM
Summary
by MITRE • 08/14/2026
IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to obtain sensitive information due to improper processing of XML external entities.
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Analysis
by VulDB Data Team • 08/14/2026
This vulnerability affects IBM i operating systems version 7.6, 7.5, 7.4, and 7.3, presenting a significant security risk through improper handling of XML external entities. The flaw enables remote authenticated attackers to extract sensitive information from the system, representing a critical weakness in the platform's security architecture. The vulnerability stems from insufficient validation and sanitization of XML input processing, allowing maliciously crafted XML documents to trigger unintended information disclosure behavior.
The technical implementation of this vulnerability aligns with common XML external entity processing flaws that have been documented across various platforms and applications. When the IBM i system processes XML data containing external entity references, it fails to properly restrict or validate these references, potentially allowing attackers to access local files, network resources, or internal system information. This represents a classic case of XML External Entity (XXE) processing vulnerability where the system's XML parser does not adequately isolate external entity declarations from internal processing.
From an operational impact perspective, this vulnerability creates multiple attack vectors for authenticated remote adversaries who can leverage it to gather sensitive data including system configurations, user credentials, application data, and potentially network topology information. The remote nature of the attack means that exploitation can occur from outside the local network perimeter, making the vulnerability particularly dangerous in enterprise environments where IBM i systems may be exposed to external networks. The authenticated requirement reduces the attack surface compared to fully unauthenticated scenarios but still represents a significant risk given that many IBM i implementations have relatively open access controls.
The vulnerability's classification aligns with CWE-611 (Improper Restriction of XML External Entity Reference) and demonstrates characteristics consistent with ATT&CK technique T1592 (Gather Victim Host Information) and T1071.004 (Application Layer Protocol: DNS). Organizations utilizing these IBM i versions face potential data breaches, regulatory compliance violations, and operational disruptions if exploited successfully. The attack chain typically involves crafting malicious XML payloads that reference external entities pointing to sensitive local resources or internal network endpoints.
Mitigation strategies should focus on implementing proper XML parser configuration with external entity processing disabled or restricted, applying the latest security patches from IBM, and implementing network segmentation to limit access to affected systems. Organizations should also consider deploying web application firewalls and monitoring solutions to detect anomalous XML processing patterns. Regular vulnerability assessments and security audits are essential to identify similar weaknesses in other system components that may present comparable risks. Additionally, implementing principle of least privilege access controls and regular credential rotation can help reduce the potential impact of successful exploitation attempts.
The vulnerability highlights the importance of proper input validation and secure coding practices within enterprise operating systems, particularly in environments where legacy systems continue to process untrusted data inputs. Organizations should also consider implementing comprehensive security monitoring solutions that can detect unusual XML processing activities and provide early warning capabilities for potential exploitation attempts. Regular security awareness training for system administrators and developers can help ensure that proper security controls are maintained throughout the system lifecycle.