Critical and high-severity vulnerabilities and zero-days: exploitation status, proof-of-concept availability, and what to patch first.
Unit 42 says the Qilin and INC ransomware groups are using CVE-2026-0257, a GlobalProtect authentication bypass patched in May, to open VPN sessions without MFA and then move on to vCenter, ESXi and Veeam.
Attackers are chaining four Plex Media Server bugs, now on CISA's exploited list, to drop a cryptominer and a traffic-relay proxy on servers that never got September's fix.
Rapid7 details intrusions where attackers chained CVE-2026-88771 and CVE-2026-88779 to get root on NetScaler ADC and Gateway, then planted HA-aware persistence and stole the appliance's credentials and keys.
PHP shipped 8.5.12, 8.4.27, 8.3.36 and 8.2.35 on Oct. 21 to fix two critical bugs nicknamed php2shell, after details leaked early. Code claiming to exploit them is already circulating.
Google and Mandiant say suspected Chinese espionage group ARMORY CASTLE has exploited a BeyondTrust Remote Support zero-day since late August. Once inside, it took root, dumped stored credentials and used the support tool to reach internal machines.