Cisco Secure Email Gateway and Secure Email and Web Manager Security Hardening Release: September 2026

Description

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Email Gateway and Cisco Secure Email and Web Manager engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. These vulnerabilities were found during internal testing. Two of them are known to be actively exploited. For more information, see Cisco Secure Email Gateway SQL Injection Vulnerability and Cisco Secure Email Gateway Arbitrary File Write Vulnerability . To assist customers in patching and streamline the disclosure process, Cisco has grouped these issues by their underlying vulnerability class — Common Weakness Enumeration (CWE) — and assigned a single Common Vulnerabilities and Exposures identifier (CVE ID) to each CWE grouping. Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-esa-dfCrfXkm Security Impact Rating: Critical CVE: CVE-2026-20353,CVE-2026-76440,CVE-2026-76441,CVE-2026-76442,CVE-2026-76443

What to do

Install the fixed versions listed in the official advisory. If you cannot update right away, apply the workarounds or mitigations it describes and limit access to the affected service.

Details

Vendor

Cisco

Product

Cisco Secure Email Gateway

CVE

CVE-2026-20353, CVE-2026-76440, CVE-2026-76441, CVE-2026-76442, CVE-2026-76443

Affected versions

Cisco Secure Email 14.0: 14.0.0-698
Cisco Secure Email 13.5: 13.5.1-277; 13.5.4-038
Cisco Secure Email 13.0: 13.0.0-392; 13.0.5-007
Cisco Secure Email 14.2: 14.2.0-620; 14.2.1-020
Cisco Secure Email 14.3: 14.3.0-032
Cisco Secure Email 15.0: 4 versions, from 15.0.0-104 to 15.0.5-016
Cisco Secure Email 15.5: 6 versions, from 15.5.0-048 to 15.5.5-014
Cisco Secure Email 16.0: 6 versions, from 16.0.0-050 to 16.0.4-016
Cisco Secure Email and Web Manager 13.6: 13.6.1-201; 13.6.2-023; 13.6.2-078
Cisco Secure Email and Web Manager 13.0: 13.0.0-249; 13.0.0-277
Cisco Secure Email and Web Manager 13.8: 4 versions, from 13.8.1-052 to 13.8.1-108
Cisco Secure Email and Web Manager 14.0: 14.0.0-404
Cisco Secure Email and Web Manager 12.8: 12.8.1-002; 12.8.1-021
Cisco Secure Email and Web Manager 14.1: 14.1.0-227
Cisco Secure Email and Web Manager 14.2: 14.2.0-203; 14.2.0-212; 14.2.0-224
Cisco Secure Email and Web Manager 14.3: 14.3.0-120
Cisco Secure Email and Web Manager 15.0: 15.0.0-334; 15.0.1-035; 15.0.2-007
Cisco Secure Email and Web Manager 15.5: 6 versions, from 15.5.1-024 to 15.5.5-006
Cisco Secure Email and Web Manager 16.0: 5 versions, from 16.0.0-195 to 16.0.4-010
Cisco Secure Email and Web Manager 16.5: 16.5.0-429 (from the advisory and NVD; check the exact builds in the official advisory)

CVSS score

9.8

Actively exploited

Not known at this time

Source

Cisco PSIRT – original advisory

Published

October 14, 2026

The description and the recommended action are quoted from the public advisory (the action is our generic advice); severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.