CVE-2026-76519
Cisco Secure Email Gateway Relative Path Traversal Vulnerability
Cisco Secure Email Gateway
A vulnerability in the Advanced Malware Protection (AMP) feature of Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to write arbitrary files on the underlying operating system. This vulnerability is due to improper handling of email attachments when the file reputation service is enabled. An attacker could exploit this vulnerability by sending an email that contains a crafted attachment through an affected device. A successful exploit could allow the attacker to write arbitrary files and execute commands with root privileges on the underlying operating system.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 14 October 2026. US federal agencies were required to remediate it by 17 October 2026.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 1.6%, which is higher than 75.2% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2026-76519 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2026-76519.
What does CVE-2026-76519 affect?
CVE-2026-76519 affects Cisco Secure Email Gateway. A vulnerability in the Advanced Malware Protection (AMP) feature of Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to write arbitrary files on the underlying operating system. This vulnerability is due to improper handling of email attachments when the file reputation service is enabled. An attacker could exploit this vulnerability by sending an email that contains a crafted attachment through an affected device. A successful exploit could allow the attacker to write arbitrary files and execute commands with root privileges on the underlying operating system.
How severe is CVE-2026-76519?
CVE-2026-76519 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 1.6%, higher than 75.2% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 17 October 2026.
How should organisations respond to CVE-2026-76519?
Apply the vendor patch for Cisco Secure Email Gateway as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.