FKIE_CVE-2025-20241
Vulnerability from fkie_nvd - Published: 2025-08-27 17:15 - Updated: 2026-06-17 08:41
Severity
Summary
A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) feature of Cisco NX-OS Software for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, adjacent attacker to cause the IS-IS process to unexpectedly restart, which could cause an affected device to reload.
This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device. A successful exploit could allow the attacker to cause the unexpected restart of the IS-IS process, which could cause the affected device to reload, resulting in a denial of service (DoS) condition.
Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unknown",
"product": "Cisco NX-OS Software",
"vendor": "Cisco",
"versions": [
{
"status": "affected",
"version": "9.2(3)"
},
{
"status": "affected",
"version": "7.0(3)I5(2)"
},
{
"status": "affected",
"version": "6.0(2)A8(7a)"
},
{
"status": "affected",
"version": "7.0(3)I4(5)"
},
{
"status": "affected",
"version": "7.0(3)I4(6)"
},
{
"status": "affected",
"version": "7.0(3)I4(3)"
},
{
"status": "affected",
"version": "9.2(2v)"
},
{
"status": "affected",
"version": "7.0(3)I4(7)"
},
{
"status": "affected",
"version": "7.0(3)I4(1)"
},
{
"status": "affected",
"version": "7.0(3)I4(8)"
},
{
"status": "affected",
"version": "7.0(3)I4(2)"
},
{
"status": "affected",
"version": "6.0(2)A8(11)"
},
{
"status": "affected",
"version": "9.2(1)"
},
{
"status": "affected",
"version": "9.2(2t)"
},
{
"status": "affected",
"version": "9.2(3y)"
},
{
"status": "affected",
"version": "7.0(3)I4(1t)"
},
{
"status": "affected",
"version": "7.0(3)I7(6z)"
},
{
"status": "affected",
"version": "9.3(2)"
},
{
"status": "affected",
"version": "7.0(3)F3(3)"
},
{
"status": "affected",
"version": "7.0(3)I7(3z)"
},
{
"status": "affected",
"version": "7.0(3)IM7(2)"
},
{
"status": "affected",
"version": "6.0(2)A8(11b)"
},
{
"status": "affected",
"version": "7.0(3)I7(5a)"
},
{
"status": "affected",
"version": "7.0(3)I6(1)"
},
{
"status": "affected",
"version": "7.0(3)I5(3b)"
},
{
"status": "affected",
"version": "9.2(4)"
},
{
"status": "affected",
"version": "6.0(2)A8(10)"
},
{
"status": "affected",
"version": "6.0(2)A8(2)"
},
{
"status": "affected",
"version": "7.0(3)IC4(4)"
},
{
"status": "affected",
"version": "7.0(3)F3(3c)"
},
{
"status": "affected",
"version": "7.0(3)F3(1)"
},
{
"status": "affected",
"version": "7.0(3)F3(5)"
},
{
"status": "affected",
"version": "7.0(3)I7(2)"
},
{
"status": "affected",
"version": "7.0(3)I5(3)"
},
{
"status": "affected",
"version": "7.0(3)I7(3)"
},
{
"status": "affected",
"version": "6.0(2)A8(6)"
},
{
"status": "affected",
"version": "7.0(3)I6(2)"
},
{
"status": "affected",
"version": "6.0(2)A8(5)"
},
{
"status": "affected",
"version": "9.3(1)"
},
{
"status": "affected",
"version": "6.0(2)A8(7)"
},
{
"status": "affected",
"version": "7.0(3)I7(6)"
},
{
"status": "affected",
"version": "6.0(2)A8(11a)"
},
{
"status": "affected",
"version": "7.0(3)I4(8z)"
},
{
"status": "affected",
"version": "7.0(3)I4(9)"
},
{
"status": "affected",
"version": "7.0(3)I7(4)"
},
{
"status": "affected",
"version": "7.0(3)I7(7)"
},
{
"status": "affected",
"version": "6.0(2)A8(9)"
},
{
"status": "affected",
"version": "6.0(2)A8(1)"
},
{
"status": "affected",
"version": "6.0(2)A8(10a)"
},
{
"status": "affected",
"version": "7.0(3)I5(1)"
},
{
"status": "affected",
"version": "9.3(1z)"
},
{
"status": "affected",
"version": "9.2(2)"
},
{
"status": "affected",
"version": "7.0(3)F3(4)"
},
{
"status": "affected",
"version": "7.0(3)I4(8b)"
},
{
"status": "affected",
"version": "6.0(2)A8(3)"
},
{
"status": "affected",
"version": "7.0(3)I4(6t)"
},
{
"status": "affected",
"version": "7.0(3)I5(3a)"
},
{
"status": "affected",
"version": "6.0(2)A8(8)"
},
{
"status": "affected",
"version": "7.0(3)I7(5)"
},
{
"status": "affected",
"version": "7.0(3)F3(3a)"
},
{
"status": "affected",
"version": "6.0(2)A8(4)"
},
{
"status": "affected",
"version": "7.0(3)I4(8a)"
},
{
"status": "affected",
"version": "7.0(3)F3(2)"
},
{
"status": "affected",
"version": "7.0(3)I4(4)"
},
{
"status": "affected",
"version": "7.0(3)I7(1)"
},
{
"status": "affected",
"version": "7.0(3)IA7(2)"
},
{
"status": "affected",
"version": "7.0(3)IA7(1)"
},
{
"status": "affected",
"version": "6.0(2)A8(7b)"
},
{
"status": "affected",
"version": "6.0(2)A8(4a)"
},
{
"status": "affected",
"version": "9.3(3)"
},
{
"status": "affected",
"version": "7.0(3)I7(8)"
},
{
"status": "affected",
"version": "9.3(4)"
},
{
"status": "affected",
"version": "9.3(5)"
},
{
"status": "affected",
"version": "7.0(3)I7(9)"
},
{
"status": "affected",
"version": "9.3(6)"
},
{
"status": "affected",
"version": "10.1(2)"
},
{
"status": "affected",
"version": "10.1(1)"
},
{
"status": "affected",
"version": "9.3(5w)"
},
{
"status": "affected",
"version": "9.3(7)"
},
{
"status": "affected",
"version": "9.3(7k)"
},
{
"status": "affected",
"version": "7.0(3)I7(9w)"
},
{
"status": "affected",
"version": "10.2(1)"
},
{
"status": "affected",
"version": "9.3(7a)"
},
{
"status": "affected",
"version": "9.3(8)"
},
{
"status": "affected",
"version": "7.0(3)I7(10)"
},
{
"status": "affected",
"version": "10.2(1q)"
},
{
"status": "affected",
"version": "10.2(2)"
},
{
"status": "affected",
"version": "9.3(9)"
},
{
"status": "affected",
"version": "10.1(2t)"
},
{
"status": "affected",
"version": "10.2(3)"
},
{
"status": "affected",
"version": "10.2(3t)"
},
{
"status": "affected",
"version": "9.3(10)"
},
{
"status": "affected",
"version": "10.2(2a)"
},
{
"status": "affected",
"version": "10.3(1)"
},
{
"status": "affected",
"version": "10.2(4)"
},
{
"status": "affected",
"version": "10.3(2)"
},
{
"status": "affected",
"version": "9.3(11)"
},
{
"status": "affected",
"version": "10.3(3)"
},
{
"status": "affected",
"version": "10.2(5)"
},
{
"status": "affected",
"version": "9.3(12)"
},
{
"status": "affected",
"version": "10.2(3v)"
},
{
"status": "affected",
"version": "10.4(1)"
},
{
"status": "affected",
"version": "10.3(99w)"
},
{
"status": "affected",
"version": "10.2(6)"
},
{
"status": "affected",
"version": "10.3(3w)"
},
{
"status": "affected",
"version": "10.3(99x)"
},
{
"status": "affected",
"version": "10.3(3o)"
},
{
"status": "affected",
"version": "10.3(4)"
},
{
"status": "affected",
"version": "10.3(3p)"
},
{
"status": "affected",
"version": "10.3(4a)"
},
{
"status": "affected",
"version": "10.4(2)"
},
{
"status": "affected",
"version": "10.3(3q)"
},
{
"status": "affected",
"version": "9.3(13)"
},
{
"status": "affected",
"version": "10.3(5)"
},
{
"status": "affected",
"version": "10.2(7)"
},
{
"status": "affected",
"version": "10.4(3)"
},
{
"status": "affected",
"version": "10.3(3x)"
},
{
"status": "affected",
"version": "10.3(4g)"
},
{
"status": "affected",
"version": "10.5(1)"
},
{
"status": "affected",
"version": "10.2(8)"
},
{
"status": "affected",
"version": "10.3(3r)"
},
{
"status": "affected",
"version": "10.3(6)"
},
{
"status": "affected",
"version": "9.3(14)"
},
{
"status": "affected",
"version": "10.4(4)"
},
{
"status": "affected",
"version": "10.3(4h)"
},
{
"status": "affected",
"version": "10.5(2)"
},
{
"status": "affected",
"version": "10.4(4g)"
}
]
}
],
"source": "psirt@cisco.com"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) feature of Cisco NX-OS Software for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, adjacent attacker to cause the IS-IS process to unexpectedly restart, which could cause an affected device to reload.\r\n\r\nThis vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device. A successful exploit could allow the attacker to cause the unexpected restart of the IS-IS process, which could cause the affected device to reload, resulting in a denial of service (DoS) condition.\r\nNote: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device."
},
{
"lang": "es",
"value": "Una vulnerabilidad en la funci\u00f3n de sistema intermedio a sistema intermedio (IS-IS) del software Cisco NX-OS para los switches Cisco Nexus de las series 3000 y 9000 en modo NX-OS independiente podr\u00eda permitir que un atacante adyacente no autenticado provoque el reinicio inesperado del proceso IS-IS, lo que podr\u00eda provocar la recarga del dispositivo afectado. Esta vulnerabilidad se debe a una validaci\u00f3n de entrada insuficiente al analizar un paquete IS-IS de entrada. Un atacante podr\u00eda explotar esta vulnerabilidad enviando un paquete IS-IS manipulado a un dispositivo afectado. Una explotaci\u00f3n exitosa podr\u00eda permitir al atacante provocar el reinicio inesperado del proceso IS-IS, lo que podr\u00eda provocar la recarga del dispositivo afectado y provocar una denegaci\u00f3n de servicio (DoS). Nota: El protocolo IS-IS es un protocolo de enrutamiento. Para explotar esta vulnerabilidad, un atacante debe estar adyacente a la capa 2 del dispositivo afectado."
}
],
"id": "CVE-2025-20241",
"lastModified": "2026-06-17T08:41:10.377",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "ADJACENT_NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.4,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 4.0,
"source": "psirt@cisco.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2025-20241",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-08-27T18:18:19.522793Z",
"version": "2.0.3"
}
}
]
},
"published": "2025-08-27T17:15:34.650",
"references": [
{
"source": "psirt@cisco.com",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-n39k-isis-dos-JhJA8Rfx"
}
],
"sourceIdentifier": "psirt@cisco.com",
"vulnStatus": "Deferred",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-733"
}
],
"source": "psirt@cisco.com",
"type": "Secondary"
}
]
}
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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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