Cisco Secure Email and Web Manager/Secure Email Gateway up to 16.0.4-016 resource control

Summaryinfo

A vulnerability marked as very critical has been reported in Cisco Secure Email and Web Manager and Secure Email Gateway. This affects an unknown part. This manipulation causes resource control. This vulnerability appears as CVE-2026-20353. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Cisco Secure Email and Web Manager and Secure Email Gateway. It has been declared as very critical. Affected by this vulnerability is an unknown code. The manipulation with an unknown input leads to a resource control vulnerability. The CWE definition for the vulnerability is CWE-664. The product does not maintain or incorrectly maintains control over a resource throughout its lifetime of creation, use, and release. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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. The vulnerabilities tracked by CVE-2026-20353 are related to issues with improper control of a resource through its lifetime that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-664.

It is possible to read the advisory at sec.cloudapps.cisco.com. This vulnerability is known as CVE-2026-20353 since 10/08/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/14/2026).

Upgrading eliminates this vulnerability.

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Productinfo

Vendor

• Cisco

Name

• Secure Email and Web Manager
• Secure Email Gateway

Version

• 13.0.0-392
• 13.0.5-007
• 13.5.1-277
• 13.5.4-038
• 14.0.0-698
• 14.2.0-620
• 14.2.1-020
• 14.3.0-032
• 15.0.0-104
• 15.0.1-030
• 15.0.3-002
• 15.0.5-016
• 15.5.0-048
• 15.5.1-055
• 15.5.2-018
• 15.5.3-022
• 15.5.4-012
• 16.0.0-050
• 16.0.0-054
• 16.0.1-017
• 16.0.2-112
• 16.0.3-044
• 16.0.4-016

License

• commercial

Website

• Vendor: https://www.cisco.com/

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