CVE-2026-20354 (GCVE-0-2026-20354)
Vulnerability from cvelistv5
Published
2026-09-02 16:14
Modified
2026-09-02 17:58
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-354 - Improper Validation of Integrity Check Value
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. 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.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Cisco | Cisco Secure Email |
Version: 14.0.0-698 Version: 13.5.1-277 Version: 13.0.0-392 Version: 14.2.0-620 Version: 13.0.5-007 Version: 13.5.4-038 Version: 14.2.1-020 Version: 14.3.0-032 Version: 15.0.0-104 Version: 15.0.1-030 Version: 15.5.0-048 Version: 15.5.1-055 Version: 15.5.2-018 Version: 16.0.0-050 Version: 15.0.3-002 Version: 16.0.0-054 Version: 15.5.3-022 Version: 16.0.1-017 Version: 15.5.4-012 Version: 16.0.4-016 Version: 15.0.5-016 Version: 16.0.2-112 Version: 16.0.3-044 Version: 16.5.0-780 |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-20354",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-02T16:49:02.578484Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-09-02T17:58:58.074Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unknown",
"product": "Cisco Secure Email",
"vendor": "Cisco",
"versions": [
{
"status": "affected",
"version": "14.0.0-698"
},
{
"status": "affected",
"version": "13.5.1-277"
},
{
"status": "affected",
"version": "13.0.0-392"
},
{
"status": "affected",
"version": "14.2.0-620"
},
{
"status": "affected",
"version": "13.0.5-007"
},
{
"status": "affected",
"version": "13.5.4-038"
},
{
"status": "affected",
"version": "14.2.1-020"
},
{
"status": "affected",
"version": "14.3.0-032"
},
{
"status": "affected",
"version": "15.0.0-104"
},
{
"status": "affected",
"version": "15.0.1-030"
},
{
"status": "affected",
"version": "15.5.0-048"
},
{
"status": "affected",
"version": "15.5.1-055"
},
{
"status": "affected",
"version": "15.5.2-018"
},
{
"status": "affected",
"version": "16.0.0-050"
},
{
"status": "affected",
"version": "15.0.3-002"
},
{
"status": "affected",
"version": "16.0.0-054"
},
{
"status": "affected",
"version": "15.5.3-022"
},
{
"status": "affected",
"version": "16.0.1-017"
},
{
"status": "affected",
"version": "15.5.4-012"
},
{
"status": "affected",
"version": "16.0.4-016"
},
{
"status": "affected",
"version": "15.0.5-016"
},
{
"status": "affected",
"version": "16.0.2-112"
},
{
"status": "affected",
"version": "16.0.3-044"
},
{
"status": "affected",
"version": "16.5.0-780"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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.\r\n\r\nThese 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."
}
],
"exploits": [
{
"lang": "en",
"value": "The Cisco Product Security Incident Response Team (PSIRT) is aware that a public announcement is available for the vulnerabilities that are described in this advisory.\r\n\r\nThe Cisco PSIRT is not aware of any malicious use of the vulnerabilities that are described in this advisory."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.9,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
},
"format": "cvssV3_1"
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-354",
"description": "Improper Validation of Integrity Check Value",
"lang": "en",
"type": "cwe"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-02T16:14:29.829Z",
"orgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
"shortName": "cisco"
},
"references": [
{
"name": "cisco-sa-esa-smime-disc-dzw4rEdY",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-smime-disc-dzw4rEdY"
}
],
"source": {
"advisory": "cisco-sa-esa-smime-disc-dzw4rEdY",
"defects": [
"CSCwu28364"
],
"discovery": "EXTERNAL"
},
"title": "Cisco Secure Email S/MIME Ciphertext Decryption Vulnerabilty"
}
},
"cveMetadata": {
"assignerOrgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
"assignerShortName": "cisco",
"cveId": "CVE-2026-20354",
"datePublished": "2026-09-02T16:14:29.829Z",
"dateReserved": "2025-10-08T11:59:15.414Z",
"dateUpdated": "2026-09-02T17:58:58.074Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…