Medium [CVE-2026-20354 +1] Cisco Secure Email Secure/Multipurpose Internet Mail Extensions Ciphertext Decryption Vulnerabilities
This medium-severity Cisco advisory covers CVE-2026-20354 and CVE-2026-20355 affecting Secure Email.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations. This bulletin covers 2 CVEs; its score, affected versions and guidance may apply to different issues within that bulletin.
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Summary
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.
- Scope: At the time of publication, these vulnerabilities affected Cisco Secure Email devices if they were running Cisco AsyncOS Software Release 16.5.0 or earlier and had S/MIME configured for communication between email gateways.
Official advisory · high-confidence parse· fetched 22 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 22 days ago·verify at source
Mitigation checklist
- There are no workarounds that address these vulnerabilities.
Official advisory · high-confidence parse· fetched 22 days ago·verify at source
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