CVE-2026-20290 (GCVE-0-2026-20290)
Vulnerability from cvelistv5 – Published: 2026-09-16 20:19 – Updated: 2026-09-17 17:29
VLAI
EPSS
VEX
Title
Cisco Secure Firewall Threat Defense Software Snort 2 SSL/TLS Denial of Service Vulnerability
Summary
A vulnerability in SSL/TLS certificate parsing in the Snort 2 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 2 Detection Engine to restart.
This vulnerability is due to incomplete validation of the SSL certificate. An attacker could exploit this vulnerability by sending a crafted SSL connection setup request to be parsed by Snort 2. A successful exploit could allow the attacker to cause the Snort 2 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition.
Severity
5.8 (Medium)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-17 17:25 UTC
CWE
- CWE-805 - Buffer Access with Incorrect Length Value
Assigner
References
1 reference
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software |
Affected:
7.0.0
Affected: 7.0.0.1 Affected: 7.0.1 Affected: 7.0.1.1 Affected: 7.0.2 Affected: 7.2.0 Affected: 7.0.2.1 Affected: 7.0.3 Affected: 7.2.0.1 Affected: 7.0.4 Affected: 7.2.1 Affected: 7.0.5 Affected: 7.3.0 Affected: 7.2.2 Affected: 7.2.3 Affected: 7.3.1 Affected: 7.2.4 Affected: 7.0.6 Affected: 7.2.5 Affected: 7.2.4.1 Affected: 7.3.1.1 Affected: 7.4.0 Affected: 7.0.6.1 Affected: 7.2.5.1 Affected: 7.4.1 Affected: 7.2.6 Affected: 7.0.6.2 Affected: 7.4.1.1 Affected: 7.2.7 Affected: 7.2.5.2 Affected: 7.3.1.2 Affected: 7.2.8 Affected: 7.6.0 Affected: 7.4.2 Affected: 7.2.8.1 Affected: 7.0.6.3 Affected: 7.4.2.1 Affected: 7.2.9 Affected: 7.0.7 Affected: 7.4.2.2 Affected: 7.2.10 Affected: 7.6.1 Affected: 7.4.2.3 Affected: 7.0.8 Affected: 7.6.2 Affected: 7.0.8.1 Affected: 7.6.2.1 Affected: 7.4.2.4 Affected: 7.2.10.2 Affected: 7.4.3 Affected: 7.6.4 Affected: 7.4.4 Affected: 7.0.9 Affected: 7.2.11 Affected: 7.4.7 |
guessed |
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"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 5.8,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L",
"version": "3.1"
},
"format": "cvssV3_1"
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-805",
"description": "Buffer Access with Incorrect Length Value",
"lang": "en",
"type": "cwe"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-16T20:19:02.761Z",
"orgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
"shortName": "cisco"
},
"references": [
{
"name": "cisco-sa-ftd-snort2-ssldos-Mw7WYX9c",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-snort2-ssldos-Mw7WYX9c"
}
],
"source": {
"advisory": "cisco-sa-ftd-snort2-ssldos-Mw7WYX9c",
"defects": [
"CSCwu03757"
],
"discovery": "EXTERNAL"
},
"title": "Cisco Secure Firewall Threat Defense Software Snort 2 SSL/TLS Denial of Service Vulnerability"
}
},
"cveMetadata": {
"assignerOrgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
"assignerShortName": "cisco",
"cveId": "CVE-2026-20290",
"datePublished": "2026-09-16T20:19:02.761Z",
"dateReserved": "2025-10-08T11:59:15.405Z",
"dateUpdated": "2026-09-17T17:29:41.938Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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