Fresh probes target critical BeyondTrust Remote Support flaw CVE-2026-102764
- Severity
- Critical
- Exploited
- Yes
- Sources
- 2
What happened
CVE-2026-102764 (CVSS 9.3, BeyondTrust advisory BT26-05) affects Remote Support 26.2.3 and earlier; the flaw is an internal messaging origin-validation weakness allowing file operations and arbitrary file upload. Previdian observed two requests from one Hong Kong IP against decoy appliances in the US and Europe, hitting POST /api/startsession with issuemenu=1&id=1&c2cjs=1&platform=thin, resembling an unreleased Metasploit module. Mandiant linked earlier zero-day exploitation to ARMORY CASTLE (UNC5221), including SAWFLY web shell deployment. Apply BT26-05-RS (supports 24.3.1 to 26.2.3), restrict external and admin access, and hunt for unknown privileged sessions and unauthorised changes.
For security analysts · Written by AI from 2 sources · Wrong?
What to do
- Apply the BT26-05-RS patch to self-hosted Remote Support appliances, upgrading older releases first.
- Limit external access to Remote Support appliances and restrict administrative interfaces to trusted networks.
- Check appliances for unknown privileged sessions, unexpected scripts, missing logs and unauthorised account or permission changes.
- If compromise is suspected, isolate the appliance, preserve forensic evidence, rebuild from a known-good state, rotate managed credentials, revoke support sessions and review new MFA registrations.
Written by AI from the sources, checked against them
Vulnerabilities
Full story timeline · 5 updates
- Fri 16 OctoberCVE-2025-61624 added to CISA’s exploited listCISA KEV
- CVE-2026-102764 added to CISA’s exploited listCISA KEV
- CISA Urges Patching Critical Vulnerability in BeyondTrust Remote SupportCISA Alerts
- CISA Adds Two Known Exploited Vulnerabilities to CatalogCISA Alerts
- Mon 2 NovemberCritical BeyondTrust Vulnerability Faces Fresh Exploitation Probes as Hackers Prepare for Mass ScanningCyber Security News
Who reported · 2 outlets
Who and what is in it
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