Daily DefSec Brief

Cyber Security News for September 3 2026 - Daily DefSec Brief

Daily DefSec Brief

Show Notes

1. Kestra workflow engine lets anyone run commands with no credentials at all — CVE-2026-49869 — CISA KEV — https://www.cisa.gov/known-exploited-vulnerabilities-catalog 2. GitSpawn lets a repository's own config run commands through your AI coding agent — CVE-2026-19592, CVE-2026-55607, CVE-2026-71963, CVE-2026-72718 — Manifold Security — https://www.manifold.security/blog/ai-coding-agents-git-hijack 3. Cisco Nexus 9000 switches take unauthenticated code execution as root — CVE-2026-20212 — Cisco PSIRT — https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-notice-f2SiMFxl 4. LiteLLM accepts any bearer token as a valid MCP session — CVE-2026-59822 — BerriAI advisory — https://github.com/BerriAI/litellm/security/advisories/GHSA-7488-6r32-c95q 5. BadHost defeats authentication anywhere Starlette rebuilds the URL — CVE-2026-48710 — CCB Belgium — https://ccb.belgium.be/advisories/warning-vulnerability-starlette-framework-and-related-frameworks-fastapi-exposes 6. Exploit published for a Cleo Harmony authentication bypass — CVE-2026-84115 — SecurityWeek — https://www.securityweek.com/exploit-published-for-fresh-cleo-harmony-vulnerability/ 7. Dropbox accounts opened through a flaw in Lenovo's email verification — BleepingComputer — https://www.bleepingcomputer.com/news/security/dropbox-accounts-breached-through-lenovo-email-verification-flaw/ 8. Fake IT support on Teams now ends in a Node.js implant and hands-on-keyboard access — Microsoft Security — https://www.microsoft.com/en-us/security/blog/2026/09/02/impersonating-it-support-threat-actors-turn-remote-session-into-enterprise-wide-access/ 9. The Gentlemen ransomware turns off EDR and backups before encrypting — Cyber Security News — https://cybersecuritynews.com/the-gentlemen-ransomware/ 10. Researcher publishes a CrowdStrike Falcon privilege-escalation exploit — Security Affairs — https://securityaffairs.com/198342/hacking/chaotic-eclipse-releases-crowdstrike-falcon-zeroday-falconflank.html 11. Windows starts switching memory integrity on by itself in October — Help Net Security — https://www.helpnetsecurity.com/2026/09/03/windows-memory-integrity-update/ 12. One AI model completed a full cyber kill chain on its own in Booz Allen's tests — The Register — https://www.theregister.com/security/2026/09/02/claude-mythos-only-model-to-complete-full-cyber-kill-chain-experts-say/5294071 13. Attackers are self-hosting a chat interface on the infrastructure they compromise — Unit 42 — https://unit42.paloaltonetworks.com/ai-tool-use-targeting-latam-orgs/ 14. Chrome ships 26 fixes including two critical use-after-free bugs — CVE-2026-84352, CVE-2026-84353 — SecurityWeek — https://www.securityweek.com/chrome-and-firefox-updates-patch-dozens-of-vulnerabilities/ 15. Teams and Outlook fail to launch on ARM Windows after the August updates — BleepingComputer — https://www.bleepingcomputer.com/news/microsoft/microsoft-teams-outlook-fail-to-launch-on-arm-based-windows-pcs/ 16. A hundred and fifty-three million driver's licence scans are for sale — Ars Technica — https://arstechnica.com/security/2026/09/my-drivers-license-is-one-of-153-million-for-sale-on-a-new-dark-website/

More from Daily DefSec Brief

Oct 23, 2026

Attackers are exploiting a third VeloCloud Orchestrator zero-day, stolen Microsoft 365 tokens were replayed against 79 organizations from one hosting range, and Railway is telling every customer to rotate their secrets. Plus eMudhra's root leaving Chrome on October 27, and a firewall whose admin password was "password". Every version number in this episode was checked against the vendor's own advisory before it aired. Today's question: How does your team keep audit findings from turning into a pay negotiation? Reply in the comments or at [email protected].

Oct 22, 2026

Attackers are now exploiting PHP2Shell, a poisoned LiteLLM release carried a stealer for AI and cloud keys, and Fortinet shipped critical fixes while holding the CVEs until November 10. Every version number and every fix in this episode was checked against the vendor's own advisory or the researchers' report before it aired. Today's question: How do you check that your security alerts still reach a person? Reply in the comments or at [email protected].

Oct 21, 2026

PHP ships fixes today for two critical flaws whose details leaked ahead of disclosure, and a certificate authority's signing keys turned out to be guessable, one of them the number four. Also: a joint advisory on SafePay ransomware, a hijacked account that swapped OVHcloud's CLI downloads for a stealer, and a test account with the password Password1. Fixes were checked against the vendor's advisory or release notes where one exists, and against the researchers' report where not. Today's question: How does your team find accounts that should have been deleted? Reply in the comments or at [email protected].

Oct 20, 2026

The NetScaler flaw that crashed appliances is a step in a root takeover whose implant tries to copy itself to the HA partner. ClickFix crews bring a signed Siemens program to run their malware, Plex servers are being hijacked a day after an exploit went public, and a fake WatchGuard download site collects VPN logins. Every version number and every fix in this episode was checked against the vendor's advisory, release notes or the CVE record before it aired. Today's question: Where does your team tell people to get the VPN client? Reply in the comments or at [email protected].

Oct 19, 2026

Attackers used ConnectWise's app credentials to enter Microsoft 365 tenants. Also: a FortiGate implant, stolen UpdraftCentral keys, NTLMv1 blocks, AOMEI's update servers, and fixes. Every version number and every fix in this episode was checked against the vendor's advisory or the CVE record before it aired. Today's question: How do you review vendor apps in your tenant? Reply in the comments or at [email protected].

See all episodes →