cisco-sa-esa-smime-disc-dzw4rEdY: Cisco Secure Email Secure/Multipurpose Internet Mail Extensions Ciphertext Decryption Vulnerabilities

Published Sep 2, 2026
·
Updated

Multiple vulnerabilities in the Secure/Multipurpose Internet Mail Extensions (S/MIME) decryption functionality of Cisco Secure Email could allow an unauthenticated, remote attacker to recover plain text from encrypted email messages.These vulnerabilities are due to insufficient validation of message integrity. An attacker could exploit these vulnerabilities by using a machine-in-the-middle technique to intercept and modify traffic between email gateways. A successful exploit could allow the attacker to obtain plaintext content from the encrypted communication.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-esa-smime-disc-dzw4rEdY

Affected Software

1 affected component
Cisco Cisco Secure Email

Event History

Sep 2, 2026
Advisory Published
via Cisco·04:00 PM
Data Sourced
via Cisco·04:00 PM
DescriptionSeverityWeakness

Frequently Asked Questions

1

What network position does an attacker need to exploit these vulnerabilities?

The attacker must be able to act as a machine-in-the-middle, intercepting and modifying traffic between email gateways. The attack can be performed remotely and does not require authentication.

2

What information could be exposed if exploitation succeeds?

A successful attack could allow recovery of plaintext content from encrypted S/MIME email communications.

3

Is there a mitigation if patching cannot be performed immediately?

No. The advisory states that there are no workarounds that address these vulnerabilities.

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