CVE-2026-20355

Published Sep 2, 2026

Last updated 2 months 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

Hype score: Not currently trending

References