Vulnerability-Lookup

GHSA-X26V-65CQ-X3PX

Vulnerability from github – Published: 2026-09-02 18:32 – Updated: 2026-09-02 18:32

Details

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.

Severity

5.9 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-20354"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-354"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-02T17:17:33Z",
    "severity": "MODERATE"
  },
  "details": "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.\n\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.",
  "id": "GHSA-x26v-65cq-x3px",
  "modified": "2026-09-02T18:32:27Z",
  "published": "2026-09-02T18:32:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20354"
    },
    {
      "type": "WEB",
      "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-smime-disc-dzw4rEdY"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-20354 (GCVE-0-2026-20354)

Vulnerability from cvelistv5 – Published: 2026-09-02 16:14 – Updated: 2026-09-02 17:58

Title

Cisco Secure Email S/MIME Ciphertext Decryption Vulnerabilty

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.

Severity

5.9 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-02 16:49 UTC

CWE

CWE-354 - Improper Validation of Integrity Check Value

Assigner

cisco mitre root

References

1 reference

URL	Tags
https://sec.cloudapps.cisco.com/security/center/c…

Impacted products

1 product

Vendor	Product	Version
Cisco	Cisco Secure Email	Affected: 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 Affected: 14.2.1-020 Affected: 14.3.0-032 Affected: 15.0.0-104 Affected: 15.0.1-030 Affected: 15.5.0-048 Affected: 15.5.1-055 Affected: 15.5.2-018 Affected: 16.0.0-050 Affected: 15.0.3-002 Affected: 16.0.0-054 Affected: 15.5.3-022 Affected: 16.0.1-017 Affected: 15.5.4-012 Affected: 16.0.4-016 Affected: 15.0.5-016 Affected: 16.0.2-112 Affected: 16.0.3-044 Affected: 16.5.0-780

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{
  "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"
            }
          ]
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      ],
      "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"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-X26V-65CQ-X3PX

CVE-2026-20354 (GCVE-0-2026-20354)

Tags

Sightings

Nomenclature