Known exploited · Cisco
CVE-2026-76519: Cisco Secure Email Gateway Relative Path Traversal Vulnerability
What it is
Cisco Secure Email Gateway contains a relative path traversal vulnerability that could allow an unauthenticated, remote attacker to write arbitrary files on the underlying operating system.
- Vendor
- Cisco
- Product
- Secure Email Gateway
- Added to KEV
- October 14, 2026
- CISA due date
- October 17, 2026
- Ransomware use
- Unknown
- Weakness
- CWE-23: Relative Path Traversal
What CISA requires
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Forensic triage
Yes
What to do now
- Find every instance of Secure Email Gateway you run, including the forgotten ones, and check its version against the vendor advisory.
- Apply the vendor's fix or mitigation, before October 17, 2026 if you are bound by CISA's deadline, sooner if it faces the internet.
- Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
References
H2 Security
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Start freeSource: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.14.