CVE-2026-76434 in Identity Services Engine Software
Summary
by MITRE • 09/16/2026
A vulnerability in the certificate import functionality of the web-based management interface of Cisco ISE and Cisco ISE-PIC could allow an authenticated, remote attacker to read arbitrary files from the affected system. To exploit this vulnerability, the attacker must have valid administrative credentials.
This vulnerability is due to insufficient validation of user-supplied input by the affected feature. An attacker could exploit this vulnerability by sending a crafted request to the web-based management interface of an affected device. A successful exploit could allow the attacker to read arbitrary files from the affected device, which could contain sensitive information.
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Analysis
by VulDB Data Team • 09/17/2026
The identified security flaw resides within the certificate import functionality of the Cisco Identity Services Engine and its Physical Interface Controller variant, specifically affecting the web-based management interface. This vulnerability allows an authenticated remote attacker with administrative privileges to perform unauthorized file reads on the underlying operating system. The core technical issue stems from insufficient validation of user-supplied input during the processing of certificate imports. When a request is submitted through the management interface, the application fails to adequately sanitize or verify the path components provided by the user. This lack of rigorous input checking enables an attacker to manipulate file paths using directory traversal techniques, such as inserting sequences like dot-dot-slash into the input fields. By crafting specific HTTP requests that exploit this parsing error, a malicious actor can bypass intended access controls and direct the system to retrieve files located outside the designated certificate storage directories.
The operational impact of this vulnerability is significant due to the high privilege level required for exploitation. Since the attacker must possess valid administrative credentials, the threat model primarily targets insider threats or scenarios where an administrator account has been compromised through phishing, credential stuffing, or other lateral movement techniques. Once exploited, the ability to read arbitrary files from the affected system can lead to a severe compromise of confidentiality. The extracted data may include sensitive configuration details, private keys associated with certificates stored on the device, database connection strings containing passwords, or other critical security parameters that are essential for maintaining the integrity and availability of the network infrastructure protected by Cisco ISE. This information disclosure facilitates further attacks, including privilege escalation, session hijacking, or the decryption of encrypted communications if private keys are obtained.
From a classification perspective, this vulnerability aligns with CWE-20 Improper Input Validation, as the root cause is the failure to properly validate and sanitize user input before processing it within file system operations. Additionally, the exploitation technique corresponds to CWE-22 Path Traversal: '../' Sequence, which describes how attackers use special characters or encoded sequences to access files outside the restricted directory. In terms of adversary behavior mapping under the MITRE ATT&CK framework, this vulnerability supports techniques related to Data from Local System Retrieval and potentially Credential Access if sensitive credentials are found within the accessed files. The attack vector is classified as remote with low complexity but requires authentication, placing it in a higher risk category than unauthenticated exploits due to the prerequisite of valid administrative access.
Mitigation strategies should focus on both immediate remediation and long-term security hardening. Cisco has released software updates that address this issue by implementing stricter input validation mechanisms within the certificate import module. Administrators are strongly advised to apply these patches immediately upon availability. In addition to patching, organizations should enforce strict least-privilege principles for administrative accounts. This includes limiting the number of users with access to the web-based management interface and ensuring that such credentials are protected by multi-factor authentication where supported. Network segmentation can also help mitigate risk by restricting access to the management interfaces from untrusted networks. Regular auditing of administrative login attempts and monitoring for anomalous file system activity on the affected devices can aid in early detection of potential exploitation attempts before significant data exfiltration occurs.