CVE-2026-20355
Cisco Secure Email S/MIME Ciphertext Decryption Vulnerabilty
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.
CVSS Vector Breakdown
AV:NAttack VectorAC:HAttack ComplexityPR:NPrivileges RequiredUI:NUser InteractionS:UScopeC:HConfidentialityI:NIntegrityA:NAvailabilityWeaknesses
Affected Products
Exploitability
Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.
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MITRE ATT&CK
1 techniqueReferences
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