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Cisco Security Advisoriescisco-sa-esa-smime-disc-dzw4rEdY

Cisco Secure Email Secure/Multipurpose Internet Mail Extensions Ciphertext Decryption Vulnerabilities

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 Security Impact Rating: Medium CVE: CVE-2026-20354,CVE-2026-20355

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MediumCVSS not listedMedium severity
Scope

What the vendor says is affected

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Update history

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    • The vendor changed the advisory's last-updated date.
Timeline

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  1. Added to SecurityAlert

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  2. Published by Cisco

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  3. Confirmed at the source

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Vulnerabilities

CVEs named in this advisory

CVE-2026-20354View CVSS, KEV, EPSS, and threat contextCVE-2026-20355View CVSS, KEV, EPSS, and threat context
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