Weekly Cybersecurity Newsletter Bulletin – Microsoft 0-day, FortiOS, PAN-OS Flaw, Revolut Data Breach, and 20+ Stories
Weekly roundup: Microsoft patches 973 flaws including two actively exploited zero-days; FortiOS CAPWAP flaw deploys PivotC2 RAT; PAN-OS root RCE disclosed.
Microsoft's September 2026 Patch Tuesday fixed 973 vulnerabilities, including two zero-days under active exploitation: CVE-2026-85880 (Windows ALPC) and CVE-2026-81963 (Windows Update Stack), both elevation-of-privilege bugs. SOCRadar reported active exploitation of CVE-2025-25249 (CVSS 9.8) in FortiOS CAPWAP, deploying a Node.js RAT called PivotC2 that exfiltrates Exchange mailboxes to Wasabi cloud storage; 178 devices were compromised out of 30,000 scanned IPs, attributed to a Russian-speaking financially motivated group. Palo Alto disclosed CVE-2026-0310, a 9.2-rated buffer overflow enabling root code execution on PA-Series firewalls, and Fortinet disclosed CVE-2026-84393, a ZTNA certificate validation MITM flaw. Cyera also revealed CVE-2026-6471 ('PostGREShell'), a 12-year-old PostgreSQL logical-decoding flaw allowing code execution via REPLICATION-privileged accounts.
FortiOS and FortiProxy ZTNA Validation Vulnerability Allows Attacker to Perform a Man-in-the-Middle Attack
Fortinet discloses high-severity certificate validation flaw CVE-2026-84393 in FortiOS and FortiProxy Agentless ZTNA portals enabling unauthenticated man-in-the-middle attacks.
Fortinet disclosed CVE-2026-84393 (CVSSv3 7.3, CWE-295) on September 8, 2026 under advisory FG-IR-26-174: improper certificate validation in the Agentless ZTNA portal of FortiOS and FortiProxy. An unauthenticated attacker on the network path could present a forged or mismatched certificate and intercept or tamper with traffic between the portal and backend destinations, with impact classified as information disclosure. Affected versions are FortiOS 7.6.1 through 7.6.6 and FortiProxy 7.6.2 through 7.6.6; the 8.0, 7.4 and 7.2 branches of both products are unaffected. Fortinet urges upgrading to 7.6.7 or later and reports no evidence of exploitation in the wild.