CVE-2024-20401

What is CVE-2024-20401?

A vulnerability in the content scanning and message filtering features of Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to overwrite arbitrary files on the underlying operating system. This vulnerability is due to improper handling of email attachments when file analysis and content filters are 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 replace any file on the underlying file system. The attacker could then perform any of the following actions: add users with root privileges, modify the device configuration, execute arbitrary code, or cause a permanent denial of service (DoS) condition on the affected device. Note: Manual intervention is required to recover from the DoS condition. Customers are advised to contact the Cisco Technical Assistance Center (TAC) to help recover a device in this condition.

Timeline

• 2024-07-17Published to the U.S. National Vulnerability Database (NVD)
• 2026-06-17NVD record last updated
• 2026-10-15First covered in a defend.network daily briefing

Affected product

Cisco Secure Email Gateway

References

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-afw-bGG2UsjH
• https://nvd.nist.gov/vuln/detail/CVE-2024-20401

Referenced in our briefings & reports

• Cisco Email Gateway RCE exploited; Nextcloud backdoors; 3 phishing platforms disrupted (2026-10-15)