Relative Path Traversal in Secure Email Gateway - CVE-2026-76519
Published: October 15, 2026
Vulnerability identifier: #VU155876
CSH Severity: Critical
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-76519
CWE-ID: CWE-23
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerability details
The vulnerability allows a remote attacker to write arbitrary files and execute commands with root privileges on the underlying operating system.
The vulnerability exists due to improper handling of email attachments in the Advanced Malware Protection (AMP) feature of Cisco Secure Email Gateway when processing email messages. A remote attacker can send an email containing a crafted attachment through an affected device to write arbitrary files and execute commands with root privileges on the underlying operating system.
Exploitation requires the File Reputation service to be enabled and assigned to a mail policy.
Note, the vulnerability is being actively exploited in the wild.
Affected software
Secure Email Gateway
How to mitigate CVE-2026-76519
Install security update from vendor's website.
Secure Email Gateway - addressed in versions 15.5.5-014, 16.5.0-780