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.
AI-powered attack exploited PaperCut flaws to hack 395 organizations
AI-driven campaign exploited PaperCut flaws CVE-2026-81578 and CVE-2026-82078, compromising 440 servers at 395 organizations in 48 countries.
GreyNoise reports a likely Russian-speaking threat actor used hundreds of AI agents combining OpenAI Codex and DeepSeek models to build, test, and refine exploits for CVE-2026-81578 and CVE-2026-82078 in PaperCut NG/MF, launching the campaign on August 31. At least 440 PaperCut instances at 395 organizations across 48 countries were compromised, with the education sector accounting for roughly half of victims and the US most targeted. Attackers harvested credentials from 280 victims, obtained OS or domain secrets from 147, and gained admin privileges at 12 organizations, using LSASS dumping, pass-the-hash, noPac, and DCSync to dump NTDS.DIT. The adversary went from empty workspace to first RCE in under four hours, and compromised at least 11 organizations within 26 seconds once the campaign launched.
Chrome V8 Zero-Day Exploited in the Wild Enables Code Execution Inside Sandbox
Google patches actively exploited Chrome V8 zero-day CVE-2026-87491, an out-of-bounds write enabling sandboxed code execution via crafted HTML pages.
Google released Chrome 153.0.8010.36/.37 fixing 230 vulnerabilities, including CVE-2026-87491, an out-of-bounds write in the V8 engine that allowed remote code execution inside the sandbox via a crafted HTML page and is confirmed to be exploited in the wild. The flaw was reported on August 6, 2026 by Jihyeon Jeong of Compsec Lab, Seoul National University, who received a $2,500 bug bounty. This is the seventh actively exploited Chrome zero-day of 2026. The update also fixes five critical flaws in WebGL and Cast, plus a high WebPackaging use-after-free (CVE-2026-87639) credited to OpenAI Codex Security.
Hackers exploit RouterOS flaws to hijack MikroTik devices without authentication
CERT Polska confirms attackers exploit chained MikroTik RouterOS SSH flaws to hijack devices without authentication; patches released in four RouterOS versions.
CERT Polska discovered six RouterOS vulnerabilities and confirmed active attacks chaining CVE-2026-67276 (CVSS 9.2, SSH authentication bypass caused by comparing only RSA key moduli) and CVE-2026-86060 (CVSS 9.2, privilege escalation via crafted usernames), dubbed MikroTrick. A third flaw, CVE-2026-67277 (CVSS 8.8) in the bandwidth-test service, can expose kernel memory or crash devices. Shadowserver counted about 122,500 MikroTik devices with SSH exposed; attackers created a privileged 'ops' account from IP 82.192.72.4, active since September 2. Fixes shipped in RouterOS 7.25beta3, 7.24.2, 7.23.4, and 6.49.21, adding startup configuration scanning with a 'Flagged' marker for unauthorized changes.
Langflow Remote Code Execution Vulnerability Exploited in Attacks (CVE-2026-0768)
Critical CVSS 9.8 RCE CVE-2026-0768 in Langflow is under active exploitation, with attackers probing for credentials and secrets.
CVE-2026-0768, a critical (CVSS 9.8) remote code execution flaw in Langflow's code validator, lets attackers execute Python code with root privileges via the validate endpoint's code parameter. VulnCheck honeypots in the UK detected Russian-origin exploitation performing reconnaissance and credential harvesting, querying environment variables like LANGFLOW_SUPERUSER and AWS keys and reading Langflow's secret key. Versions before 1.4.2 are affected; no vendor advisory or public PoC was available at reporting time.
Attackers Exploit Critical Langflow and Rails Flaws in Credential
VulnCheck reports active exploitation of critical Langflow CVE-2026-0768 and Rails CVE-2026-66066 for credential harvesting, with detections rising to 360.
VulnCheck observed active exploitation of CVE-2026-0768 (CVSS 9.8) in Langflow and CVE-2026-66066 'KindaRails2Shell' (CVSS 9.5) in Ruby on Rails, with detections rising from 50 on August 30, 2026 to 360 by September 1. The Rails flaw allows unauthenticated arbitrary file reads, leaking secret_key_base, Rails master key, database passwords, cloud credentials and API tokens, ultimately enabling RCE; the patch still leaves the variation-key Marshal deserialization RCE gadget functional. Observed chains include a Python credential harvester with SimpleHelp remote access via CVE-2026-5027, and weaponization of CVE-2025-3248 to enlist hosts into an XMR mining botnet after disabling auditd. More than 7,100 exposed vulnerable Ruby on Rails instances and over 15,000 successful exploitation attempts across three Langflow flaws were recorded.