FKIE_CVE-2026-20135
Vulnerability from fkie_nvd - Published: 2026-09-16 21:17 - Updated: 2026-09-17 14:17
Severity
Summary
A vulnerability in the TLS 1.3 implementation in Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition.
This vulnerability is due to improper buffer management during the TLS 1.3 connection. An attacker could exploit this vulnerability by sending a crafted TLS 1.3 packet to an affected system through a TLS 1.3-enabled listening socket. A successful exploit could allow the attacker to cause the LINA process to crash, which would cause the device to reload. The reload can happen before or after authentication of the connection.Note: TLS 1.3 connections include both data traffic and user-management traffic.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unknown",
"product": "Cisco Secure Firewall Threat Defense (FTD) Software",
"vendor": "Cisco",
"versions": [
{
"status": "affected",
"version": "7.0.0"
},
{
"status": "affected",
"version": "7.0.0.1"
},
{
"status": "affected",
"version": "7.0.1"
},
{
"status": "affected",
"version": "7.0.1.1"
},
{
"status": "affected",
"version": "7.0.2"
},
{
"status": "affected",
"version": "7.2.0"
},
{
"status": "affected",
"version": "7.0.2.1"
},
{
"status": "affected",
"version": "7.0.3"
},
{
"status": "affected",
"version": "7.2.0.1"
},
{
"status": "affected",
"version": "7.0.4"
},
{
"status": "affected",
"version": "7.2.1"
},
{
"status": "affected",
"version": "7.0.5"
},
{
"status": "affected",
"version": "7.3.0"
},
{
"status": "affected",
"version": "7.2.2"
},
{
"status": "affected",
"version": "7.2.3"
},
{
"status": "affected",
"version": "7.3.1"
},
{
"status": "affected",
"version": "7.2.4"
},
{
"status": "affected",
"version": "7.0.6"
},
{
"status": "affected",
"version": "7.2.5"
},
{
"status": "affected",
"version": "7.2.4.1"
},
{
"status": "affected",
"version": "7.3.1.1"
},
{
"status": "affected",
"version": "7.4.0"
},
{
"status": "affected",
"version": "7.0.6.1"
},
{
"status": "affected",
"version": "7.2.5.1"
},
{
"status": "affected",
"version": "7.4.1"
},
{
"status": "affected",
"version": "7.2.6"
},
{
"status": "affected",
"version": "7.0.6.2"
},
{
"status": "affected",
"version": "7.4.1.1"
},
{
"status": "affected",
"version": "7.2.7"
},
{
"status": "affected",
"version": "7.2.5.2"
},
{
"status": "affected",
"version": "7.3.1.2"
},
{
"status": "affected",
"version": "7.2.8"
},
{
"status": "affected",
"version": "7.6.0"
},
{
"status": "affected",
"version": "7.4.2"
},
{
"status": "affected",
"version": "7.2.8.1"
},
{
"status": "affected",
"version": "7.0.6.3"
},
{
"status": "affected",
"version": "7.4.2.1"
},
{
"status": "affected",
"version": "7.2.9"
},
{
"status": "affected",
"version": "7.0.7"
},
{
"status": "affected",
"version": "7.7.0"
},
{
"status": "affected",
"version": "7.4.2.2"
},
{
"status": "affected",
"version": "7.2.10"
},
{
"status": "affected",
"version": "7.6.1"
},
{
"status": "affected",
"version": "7.4.2.3"
},
{
"status": "affected",
"version": "7.0.8"
},
{
"status": "affected",
"version": "7.6.2"
},
{
"status": "affected",
"version": "7.7.10"
},
{
"status": "affected",
"version": "7.7.11"
},
{
"status": "affected",
"version": "7.0.8.1"
},
{
"status": "affected",
"version": "7.6.2.1"
},
{
"status": "affected",
"version": "7.7.10.1"
},
{
"status": "affected",
"version": "7.4.2.4"
},
{
"status": "affected",
"version": "7.2.10.2"
},
{
"status": "affected",
"version": "7.4.3"
},
{
"status": "affected",
"version": "7.6.4"
},
{
"status": "affected",
"version": "7.4.4"
},
{
"status": "affected",
"version": "7.0.9"
},
{
"status": "affected",
"version": "7.2.11"
}
]
}
],
"source": "psirt@cisco.com"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "A vulnerability in the TLS 1.3 implementation in Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to improper buffer management during the TLS 1.3 connection. An attacker could exploit this vulnerability by sending a crafted TLS 1.3 packet to an affected system through a TLS 1.3-enabled listening socket. A successful exploit could allow the attacker to cause the LINA process to crash, which would cause the device to reload. The reload can happen before or after authentication of the connection.Note:\u0026nbsp;TLS 1.3 connections include both data traffic and user-management traffic."
}
],
"id": "CVE-2026-20135",
"lastModified": "2026-09-17T14:17:12.670",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.6,
"baseSeverity": "HIGH",
"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:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 4.0,
"source": "psirt@cisco.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-20135",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-17T13:35:03.490455Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-09-16T21:17:07.587",
"references": [
{
"source": "psirt@cisco.com",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls1.3-dos-dLxwFWgF"
}
],
"sourceIdentifier": "psirt@cisco.com",
"vulnStatus": "Received",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-415"
}
],
"source": "psirt@cisco.com",
"type": "Secondary"
}
]
}
Loading…
Loading…
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.
Loading…
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.
Loading…
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.
Loading…