The Brevo supply-chain attack involved attackers leveraging a compromised Cloudflare API key to inject malware into more than 100,000 websites that use Brevo services. This attack was not a direct breach of customer environments but exploited trusted infrastructure and embedded scripts, demonstrating how third-party integrations and API keys can become critical security boundaries. The compromise allowed widespread malicious script injection, affecting a large number of downstream websites relying on Brevo.

Over 100,000 websites using Brevo services were affected by injected malicious scripts due to the compromised Cloudflare API key. This supply-chain compromise potentially exposed these websites and their users to malware, undermining trust in Brevo's service and highlighting risks inherent in third-party dependencies and API key management.

No specific patch or remediation details are provided. Organizations using Brevo services should monitor vendor advisories for updates and consider reviewing API key management and third-party integration security. Given the nature of the supply-chain attack, remediation likely involves revoking and rotating compromised API keys and removing injected malicious scripts. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.