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Vulnerabilities & CVEs BleepingComputer 1 month ago

Cisco patches Secure Email Gateway zero-day exploited in attacks

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CyberNew Threat Research Desk
• Original Reporting: BleepingComputer
CyberNew Threat Intel Assessment
Assessed Severity: CRITICAL
Impacted Surface
Enterprise Perimeter & Network Defense
Intelligence Sector
Vulnerabilities & CVEs

Analyst Takeaway

"Cisco warned customers to patch a critical Secure Email Gateway zero-day security flaw that threat actors have been exploiting in attacks. "In September 2026, the Cisco PSIRT became aware of active exploitation of this vulnerability," the company warned in a Monday security advisory. The security flaw (tracked as CVE-2026-76461 ) was found in the email parsing of Cisco AsyncOS Software for Cisco..."

Recommended Defense & Mitigation

  • Emergency Patching: Prioritize vendor patches and CVE mitigation across internet-facing assets immediately.
  • Perimeter Audit: Inspect perimeter firewall logs and hunt for unauthorized RCE indicators.
Curated & Verified by CyberNew Threat Intelligence Desk Standard Defense Framework (NIST / MITRE ATT&CK)

Cisco

Cisco warned customers to patch a critical Secure Email Gateway zero-day security flaw that threat actors have been exploiting in attacks.

"In September 2026, the Cisco PSIRT became aware of active exploitation of this vulnerability," the company warned in a Monday security advisory.

The security flaw (tracked as CVE-2026-76461) was found in the email parsing of Cisco AsyncOS Software for Cisco Secure Email Gateway and affects virtual and physical appliances, regardless of the device configuration.

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Source Verification & Original Intelligence

This threat report was reviewed by CyberNew analysts and cross-referenced with primary security disclosures from BleepingComputer.

Primary Advisory →