CVE-2026-0689 identifies a security weakness in Extreme Networks' ExtremeCloud IQ - Site Engine (XIQ-SE) versions before 26.2.10, specifically version 25.5.12.6 and earlier. The vulnerability arises from insufficient protection of credentials within the Network Access Control (NAC) administration interface. Although the user interface masks sensitive parameters such as passwords or keys, the underlying HTTP responses returned by the application contain the actual credential values in plaintext. This discrepancy allows an authenticated NAC administrator—who already has high privileges—to extract stored secrets that exceed their intended access permissions. The root cause is classified under CWE-522, which refers to insufficiently protected credentials. The vulnerability does not require user interaction or additional authentication beyond the NAC administrator role, making it easier to exploit within compromised or insider-threat scenarios. The CVSS v4.0 score is 6.0 (medium severity), reflecting network attack vector, low attack complexity, no user interaction, and high impact on confidentiality and integrity but no impact on availability. No public exploits have been reported yet, and no patches were linked at the time of disclosure. The vulnerability was responsibly disclosed by the Lockheed Martin Red Team and coordinated with Extreme Networks. This flaw could enable unauthorized access to sensitive credentials, potentially facilitating lateral movement, privilege escalation, or further compromise within affected networks.

The primary impact of CVE-2026-0689 is the unauthorized disclosure of sensitive credentials within ExtremeCloud IQ - Site Engine environments. Since the vulnerability allows an authenticated NAC administrator to retrieve plaintext credentials that should be masked, it can lead to privilege escalation or unauthorized access to other network resources if those credentials are reused or provide broader access. This undermines confidentiality and integrity of network security controls. Organizations relying on XIQ-SE for network access control and device management may face increased risk of insider threats or compromised administrator accounts being leveraged to extract secrets. Although availability is not affected, the exposure of credentials can facilitate further attacks such as lateral movement, unauthorized configuration changes, or data exfiltration. The impact is particularly critical in environments with sensitive or regulated data, such as government, defense, finance, and critical infrastructure sectors. The lack of known exploits reduces immediate risk but does not eliminate the threat, especially given the high privileges required to exploit the vulnerability.

To mitigate CVE-2026-0689, organizations should prioritize upgrading ExtremeCloud IQ - Site Engine to version 26.2.10 or later once available, as this will contain the official fix. Until patches are applied, restrict NAC administrator privileges strictly to trusted personnel and implement strong multi-factor authentication to reduce the risk of compromised accounts. Monitor and audit NAC administrator activities for unusual access patterns or attempts to retrieve sensitive parameters. Network segmentation should be enforced to limit administrative interface exposure to trusted management networks only. Employ network-level protections such as web application firewalls (WAFs) to detect and block suspicious HTTP requests targeting the NAC interface. Additionally, review and rotate any credentials potentially exposed through this vulnerability to prevent misuse. Finally, maintain an incident response plan that includes steps for credential compromise scenarios and ensure timely communication with Extreme Networks for updates or patches.