CTI · corroborated · 2026-09-19

Brevo Supply Chain Attack: Cloudflare Worker injected malicious code across 100,000+ sites

Full story & timeline

MITRE ATT&CK

• T1195 Supply Chain Compromise Initial Access
• T1659 Content Injection Initial Access
• T1078 Valid Accounts Stealth

Indicators

No curated indicators tied to this case.

Detections

No detection content yet — case analysis did not yield signal-specific telemetry. Check back after the next daily CTI pass.

References

• https://sansec.io/research/brevo-supply-chain-attack
• https://bleepingcomputer.com/news/security/brevo-
• https://securityweek.com/
• https://theperimetersite.com/