16 September 2026
1. What is being reported?
Cisco Secure Email Gateway, a tool many businesses use to protect their email from spam and harmful content, has a security weakness that hackers are already exploiting. This kind of flaw is called a zero-day because it was unknown before attacks began. The problem could let attackers get past email defences and deliver malicious emails.
2. What this means in plain English
If your organisation uses Cisco Secure Email Gateway, this vulnerability could let attackers send harmful emails that appear safe, increasing the risk of phishing scams or malware infections. This could lead to data loss, financial harm, or disruption of your business operations.
3. Could this affect a small business?
Small businesses and charities using Cisco Secure Email Gateway for email protection could be affected. If you do not use this Cisco product, you are unlikely to be impacted by this specific issue.
4. What to do now
- Check if your organisation uses Cisco Secure Email Gateway for email security.
- If yes, ensure the latest security updates and patches from Cisco are installed immediately.
- Review your email filtering settings and monitor for unusual email activity.
- Ask your IT provider to confirm that your email security systems are fully updated and protected.
5. Ask your IT provider
Can you confirm whether our Cisco Secure Email Gateway is patched against the recent zero-day vulnerability actively exploited in attacks?
6. Bottom line
If you use Cisco Secure Email Gateway, update it now to stop hackers exploiting this serious email security flaw.
Information based on reputable security reporting and CISA KEV.