CVE-2026-20011

Multiple Cisco products are affected by a vulnerability in the Snort 3 SMTP MIME Decoder that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart. This vulnerability is due to a lack of error checking when the MIME fields of the SMTP header are parsed. An attacker could exploit this vulnerability by sending crafted SMTP packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts.

CVSS v3 5.8 MEDIUM

5.8^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope CHANGED

References

Link	Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-mime-vulns-bkXjcKkt

Configurations

No configuration.

History

21 Oct 2026, 17:18

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-21 17:18

Updated : 2026-10-22 14:17

NVD link : CVE-2026-20011

Mitre link : CVE-2026-20011

CVE.ORG link : CVE-2026-20011

JSON object : View

Products Affected

No product.

CWE

CWE-805

Buffer Access with Incorrect Length Value

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{"status": "affected", "version": "17.18.2"}, {"status": "affected", "version": "26.1.1"}, {"status": "affected", "version": "17.15.5"}, {"status": "affected", "version": "17.15.5a"}, {"status": "affected", "version": "17.12.7"}, {"status": "affected", "version": "17.12.7a"}, {"status": "affected", "version": "17.12.7b"}, {"status": "affected", "version": "17.9.9"}, {"status": "affected", "version": "17.12.8"}, {"status": "affected", "version": "17.15.6"}, {"status": "affected", "version": "17.18.4"}, {"status": "affected", "version": "26.1.2"}], "defaultStatus": "unknown"}]}], "published": "2026-10-21T17:18:26.640", "references": [{"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-mime-vulns-bkXjcKkt", "source": "psirt@cisco.com"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "psirt@cisco.com", "description": [{"lang": "en", "value": "CWE-805"}]}], "descriptions": [{"lang": "en", "value": "Multiple Cisco products are affected by a vulnerability in the Snort 3 SMTP MIME Decoder that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart.\r\n\r\nThis vulnerability is due to a lack of error checking when the MIME fields of the SMTP header are parsed. An attacker could exploit this vulnerability by sending crafted SMTP packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts."}], "lastModified": "2026-10-22T14:17:39.607", "sourceIdentifier": "psirt@cisco.com"}