CVE-2026-76442: Unbounded Input in Cisco Secure Email Gateway Causes DoS

Cisco released fixes on 14 September 2026 for five vulnerabilities in its email security products, including CVE-2026-76442 in Secure Email Gateway and Secure Email and Web Manager. An unchecked numeric value causes resource exhaustion and denial of service; independent scoring rates it 7.5. Fixed releases: 15.5.5-014 and 16.5.0-780 for the gateway, 15.5.5-006 and 16.5.0-429 for the manager.

• CVE-2026-76442 is an unbounded numeric input flaw rated 7.5, causing denial of service
• Affects Secure Email Gateway and Secure Email and Web Manager 15.5, 16.0 and 16.5
• Fixed releases: 15.5.5-014 and 16.5.0-780 for gateway, 15.5.5-006 and 16.5.0-429 for manager
• ZoomEye identifies 1,781 assets matching the Cisco Secure Email Gateway fingerprint