Original Article Summary

CISA is aware of critical authentication bypass vulnerability CVE-2026-102764, affecting BeyondTrust Remote Support (formerly Bomgar) versions 26.2.3 and earlier. Patches are available for supported versions (24.3.1 and later); organizations using older versions must upgrade first. Cyber threat actors are actively exploiting the vulnerability to gain initial access, then establishing persistence, escalating privileges, and moving laterally. CISA added CVE-2026-102764 to its Known Exploited Vulnerabilities (KEV) catalog on Oct. 16, 2026. CISA urges organizations with affected self-hosted Remote Support appliances to immediately take the following actions: Apply the BT26-05-RS patch, as outlined in BeyondTrust’s Security Advisory BT26-05. Organizations on a self-hosted Remote Support version older than 24.3.1 will need to upgrade to a newer version to apply the patch. Organizations using BeyondTrust-hosted (SaaS) Remote Support deployments have already been patched. Review BeyondTrust’s blog ARMORY CASTLE and BT26-05: What Security Teams Need to Know for detailed information on the vulnerability and recommended response and mitigation actions. Limit external access to the Remote Support appliance to the services needed to support users and customers. Restrict access to administrative interfaces to trusted networks. Review BeyondTrust’s B Series Appliance on-premises security for additional guidance on securing network connectivity for self-hosted Remote Support appliances. Organizations with affected self-hosted Remote Support appliances should conduct network and memory forensics to identify evidence of potential compromise. If your organization suspects a compromise, CISA recommends taking the following actions: Isolate any suspected or confirmed compromised appliances. Collect a snapshot of virtual appliances or forensic image for physical appliances to conduct future forensics, immediately forward appliance syslog and session events to the SIEM, and collect any additional logs, such as web application firewall, reverse-proxy, or perimeter firewall logs for the exposure window. Consult BeyondTrust’s Syslog guide for additional information on forwarding appliance logs and session events. Conduct network and forensic investigations for evidence of compromise. Additionally, hunt for indicators of threat actor activity, including unrecognized privileged or administrative sessions, unrecognized script files, unexpected gaps in logs or log forwarding, and unauthorized account, permission, or session-policy changes. Consult CISA’s Binding Operational Directive (BOD) 26-04: Implementation Guidance for Prioritizing Security Updates Based on Risk to assist with prioritizing vulnerability remediation. Rebuild from a known-good state and apply the BT26-05-RS patch. Then rotate every credential the appliance stored or injected, revoke all active support sessions, and review new multifactor authentication registrations on privileged accounts. CISA urges organizations to review the BeyondTrust security advisory and resources noted above and apply necessary updates. CISA also recommends reviewing Mandiant’s blog, ARMORY CASTLE Exploits BeyondTrust, for additional hunt and isolation guidance and detections. Disclaimer The information in this report is being provided “as is” for informational purposes only. CISA does not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by CISA.