CVE-2025-20153: secure email Access Control Flaw — Fix

Description

A vulnerability in the email filtering mechanism of Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to bypass the configured rules and allow emails that should have been denied to flow through an affected device.   This vulnerability is due to improper handling of email that passes through an affected device. An attacker could exploit this vulnerability by sending a crafted email through the affected device. A successful exploit could allow the attacker to bypass email filters on the affected device.

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CVSS v3.1 Score

5.8

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Weakness Type (CWE)

CWE-284 CWE-284

Affected Products

Vendor	Product	Versions
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All
cisco	secure_email_gateway	All

References

Advisories & Patches

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-mailpol-bypass-5nVcJZMw

Frequently Asked Questions

What is CVE-2025-20153? +

A vulnerability in the email filtering mechanism of Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to bypass the configured rules and allow emails that should have been denied to flow through an affected device.   This vulnerability is due to improper handling of email that passes through an affected device. An attacker could exploit this vulnerability by sending a crafted email through the affected device. A successful exploit could allow the attacker to bypass email filters on the affected device. It has a CVSS v3.1 base score of 5.8 (MEDIUM).

How severe is CVE-2025-20153? +

CVE-2025-20153 has a CVSS v3.1 score of 5.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-20153? +

CVE-2025-20153 affects products from cisco, specifically: secure_email_gateway. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-20153? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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