CVE-2026-91458 in Outside In Technology
Summary
by MITRE • 10/21/2026
Vulnerability in the Oracle Outside In Technology product of Oracle Fusion Middleware (component: Outside In Core). The supported version that is affected is 8.5.8. Easily exploitable vulnerability allows unauthenticated attacker with logon to the infrastructure where Oracle Outside In Technology executes to compromise Oracle Outside In Technology. Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in takeover of Oracle Outside In Technology. CVSS 3.1 Base Score 7.8 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).
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Analysis
by VulDB Data Team • 10/21/2026
The vulnerability identified in Oracle Outside In Technology version 8.5.8 represents a critical security flaw within the core processing engine of this widely deployed document conversion and analysis library. Oracle Outside In is frequently integrated into enterprise applications to parse, convert, or preview various file formats such as PDFs, Microsoft Office documents, images, and CAD files without requiring the original application software. The specific component affected is the Outside In Core, which handles the low-level parsing of these complex binary structures. This vulnerability allows an unauthenticated attacker who has network access to the infrastructure hosting the Oracle Fusion Middleware environment to compromise the system. However, exploitation requires a significant prerequisite: human interaction from a victim other than the initial attacker. This typically implies that the attack vector involves social engineering or诱骗 techniques where a user is tricked into opening a maliciously crafted file within an application utilizing this library.
From a technical perspective, this flaw likely stems from improper validation of input data structures during the parsing process. When Oracle Outside In Technology processes specially constructed files containing malformed headers, embedded objects, or corrupted metadata, it may fail to correctly handle memory allocation or boundary checks. This can lead to conditions such as buffer overflows, heap corruption, or arbitrary code execution vulnerabilities within the context of the application using the library. Because the vulnerability allows for a takeover of Oracle Outside In Technology, an attacker could potentially execute arbitrary commands on the host system with the privileges of the process running the middleware service. The requirement for human interaction classifies this as a client-side attack vector where the victim must actively engage with malicious content, often categorized under CWE-20 Improper Input Validation or CWE-119 Memory Corruption based on common patterns in such parsing engines.
The operational impact of successfully exploiting this vulnerability is severe, aligning with a CVSS 3.1 Base Score of 7.8. The vector string (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) indicates that while the attack requires local network access and user interaction, it results in high impacts on confidentiality, integrity, and availability. An attacker who gains control over the Outside In Technology component can escalate privileges to compromise the underlying operating system if the service runs with elevated permissions. This could lead to data exfiltration of sensitive documents processed by the middleware, modification or deletion of critical business files, and disruption of services relying on document conversion capabilities. The lack of authentication requirement for the initial network access means that any user within the internal network perimeter can attempt exploitation, making it a significant risk in environments where file sharing is common.
In terms of threat modeling, this vulnerability maps to MITRE ATT&CK techniques involving Initial Access via Spearphishing Attachment and Execution via User Interaction. Attackers would typically craft malicious documents designed to trigger the parsing flaw when opened by an employee using enterprise software like email clients, document viewers, or web applications integrated with Oracle Fusion Middleware. The persistence of such a vulnerability poses long-term risks as legacy systems often continue running outdated versions due to compatibility concerns. Mitigation strategies must prioritize immediate patching through official Oracle Critical Patch Updates if available for version 8.5.8. In cases where patching is not immediately feasible, organizations should implement strict input validation at the application layer before passing files to Outside In Technology. Additionally, deploying network segmentation to restrict access to middleware servers and enforcing least-privilege principles for service accounts can reduce the blast radius of a potential compromise. Security awareness training is also crucial to mitigate the human interaction aspect by educating users against opening unexpected or suspicious file attachments from untrusted sources.