CVE-2026-20355

Published Sep 2, 2026

Last updated 2 days ago

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-20355 is a vulnerability found within the Secure/Multipurpose Internet Mail Extensions (S/MIME) decryption functionality of Cisco Secure Email. This flaw, along with others, arises from insufficient validation of message integrity. An attacker could exploit this vulnerability by employing a machine-in-the-middle (MitM) technique to intercept and modify traffic as it passes between email gateways. Successful exploitation could enable the attacker to recover plaintext content from otherwise encrypted email communications.

Description
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.
Source
psirt@cisco.com
NVD status
Awaiting Analysis

Risk scores

CVSS 3.1

Type
Secondary
Base score
5.9
Impact score
3.6
Exploitability score
2.2
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Severity
MEDIUM

Weaknesses

psirt@cisco.com
CWE-345

Social media

Hype score is a measure of social media activity compared against trending CVEs from the past 12 months. Max score 100.

Hype score

8