CVE-2026-20354Medium· 5.9▾ SunlitMultiple 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. Th…
▾ Sunlit zone — Low / medium · no exploitation signal
impact 32.5 · likelihood 0 · exploitation 0
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Exploit-prediction probability, daily snapshots since Sep 8.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CSAF
Last analysed / modified upstream
0.1%
0.1% → 0.2%
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.
Cisco Secure Email Secure/Multipurpose Internet Mail Extensions Ciphertext Decryption Vulnerabilities. Released 2026-09-02, updated 2026-09-08.
Affected:
Cisco has released software updates that address this vulnerability. https://software.cisco.com
Connected by shared product, vendor, weakness, or advisory.
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