CVE-2026-20355

Cisco Secure Email S/MIME Ciphertext Decryption Vulnerabilty

At a glance

Severity
MEDIUM 5.9
EPSS
EPSS 0.20 % · percentile 10 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
cisco
NVD status
Awaiting Analysis

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.

Scores

VersionScoreVectorScored by
CVSS 3.1MEDIUM 5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:Ncisco
CVSS 3.1MEDIUM 5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:NNVD · psirt@cisco.com (Secondary)

Weaknesses (CWE)

European references

Affected products

ProductVersions
Cisco · Cisco Secure Emailaffected 14.0.0-698 ; affected 13.5.1-277 ; affected 13.0.0-392 ; affected 14.2.0-620 ; affected 13.0.5-007 ; affected 13.5.4-038

References

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD