Cisco Releases Advisory For Critical Vulnerability in Cisco Async OS Affecting Secure Email Gateway
Successful exploitation of CVE-2026-76519 could allow an unauthenticated remote attacker to write arbitrary files and execute commands with root privileges
Summary
Successful exploitation of CVE-2026-76519 could allow an unauthenticated remote attacker to write arbitrary files and execute commands with root privileges
Affected platforms
The following platforms are known to be affected:
Threat details
Exploitation of CVE-2026-76519
Cisco is aware of active exploitation of CVE-2026-76519, and the vulnerability was added to CISA's Known Exploited Vulnerabilities (KEV) Catalog.
The NHS England National CSOC assesses further exploitation as likely.
Introduction
Cisco has released a security advisory to address a critical vulnerability in Cisco Secure Email Gateway. The vulnerability could allow an unauthenticated, remote attacker to write arbitrary files and execute commands with root privileges on the underlying operating system.
- CVE-2026-76519 - Relative path traversal vulnerability - CVSS v3.1 score 9.8
Remediation advice
Affected organisations are encouraged to review Cisco advisory Cisco Secure Email Gateway Arbitrary File Write Vulnerability and apply the relevant update as soon as possible.
Definitive source of threat updates
Last edited: 15 October 2026 12:28 pm