Vulnerability-Lookup

GHSA-95M8-QGXC-HCQX

Vulnerability from github – Published: 2026-03-11 18:30 – Updated: 2026-03-11 18:30

Details

This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and 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 and must have formed an adjacency.

Severity ?

7.4 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-20074"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1287"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-11T17:16:55Z",
    "severity": "HIGH"
  },
  "details": "A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly.\n\nThis vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and a denial of service (DoS) condition.\nNote: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and must have formed an adjacency.\u0026nbsp;\u0026nbsp;",
  "id": "GHSA-95m8-qgxc-hcqx",
  "modified": "2026-03-11T18:30:33Z",
  "published": "2026-03-11T18:30:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20074"
    },
    {
      "type": "WEB",
      "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzK"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-20074 (GCVE-0-2026-20074)

Vulnerability from cvelistv5 – Published: 2026-03-11 16:31 – Updated: 2026-03-11 17:20

Title

Cisco IOS XR Software Multi-Instance Intermediate System-to-Intermediate System Denial of Service Vulnerability

Summary

A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly. This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and 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 and must have formed an adjacency.  

Severity ?

7.4 (High)


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

CWE

CWE-1287 - Improper Validation of Specified Type of Input

Assigner

cisco

References

URL

Tags

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

Impacted products

	Vendor	Product	Version
	Cisco	Cisco IOS XR Software	Affected: 7.8.1 Affected: 7.9.1 Affected: 7.10.1 Affected: 7.8.2 Affected: 7.8.22 Affected: 7.9.2 Affected: 7.11.1 Affected: 7.9.21 Affected: 7.10.2 Affected: 24.1.1 Affected: 7.11.2 Affected: 24.2.1 Affected: 24.1.2 Affected: 24.2.11 Affected: 24.3.1 Affected: 24.4.1 Affected: 24.2.2 Affected: 7.8.23 Affected: 7.11.21 Affected: 24.2.20 Affected: 24.3.2 Affected: 24.4.10 Affected: 25.1.1 Affected: 24.4.2 Affected: 24.3.20 Affected: 24.4.15 Affected: 25.2.1 Affected: 25.1.2 Affected: 24.3.30 Affected: 24.4.30 Affected: 24.2.21 Affected: 25.2.15

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-20074",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-11T17:04:46.266844Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-11T17:20:21.640Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Cisco IOS XR Software",
          "vendor": "Cisco",
          "versions": [
            {
              "status": "affected",
              "version": "7.8.1"
            },
            {
              "status": "affected",
              "version": "7.9.1"
            },
            {
              "status": "affected",
              "version": "7.10.1"
            },
            {
              "status": "affected",
              "version": "7.8.2"
            },
            {
              "status": "affected",
              "version": "7.8.22"
            },
            {
              "status": "affected",
              "version": "7.9.2"
            },
            {
              "status": "affected",
              "version": "7.11.1"
            },
            {
              "status": "affected",
              "version": "7.9.21"
            },
            {
              "status": "affected",
              "version": "7.10.2"
            },
            {
              "status": "affected",
              "version": "24.1.1"
            },
            {
              "status": "affected",
              "version": "7.11.2"
            },
            {
              "status": "affected",
              "version": "24.2.1"
            },
            {
              "status": "affected",
              "version": "24.1.2"
            },
            {
              "status": "affected",
              "version": "24.2.11"
            },
            {
              "status": "affected",
              "version": "24.3.1"
            },
            {
              "status": "affected",
              "version": "24.4.1"
            },
            {
              "status": "affected",
              "version": "24.2.2"
            },
            {
              "status": "affected",
              "version": "7.8.23"
            },
            {
              "status": "affected",
              "version": "7.11.21"
            },
            {
              "status": "affected",
              "version": "24.2.20"
            },
            {
              "status": "affected",
              "version": "24.3.2"
            },
            {
              "status": "affected",
              "version": "24.4.10"
            },
            {
              "status": "affected",
              "version": "25.1.1"
            },
            {
              "status": "affected",
              "version": "24.4.2"
            },
            {
              "status": "affected",
              "version": "24.3.20"
            },
            {
              "status": "affected",
              "version": "24.4.15"
            },
            {
              "status": "affected",
              "version": "25.2.1"
            },
            {
              "status": "affected",
              "version": "25.1.2"
            },
            {
              "status": "affected",
              "version": "24.3.30"
            },
            {
              "status": "affected",
              "version": "24.4.30"
            },
            {
              "status": "affected",
              "version": "24.2.21"
            },
            {
              "status": "affected",
              "version": "25.2.15"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly.\r\n\r\nThis vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and 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 and must have formed an adjacency.\u0026nbsp;\u0026nbsp;"
        }
      ],
      "exploits": [
        {
          "lang": "en",
          "value": "The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "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"
          },
          "format": "cvssV3_1"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1287",
              "description": "Improper Validation of Specified Type of Input",
              "lang": "en",
              "type": "cwe"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-11T16:31:14.712Z",
        "orgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
        "shortName": "cisco"
      },
      "references": [
        {
          "name": "cisco-sa-isis-dos-kDMxpSzK",
          "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzK"
        }
      ],
      "source": {
        "advisory": "cisco-sa-isis-dos-kDMxpSzK",
        "defects": [
          "CSCwq71827"
        ],
        "discovery": "INTERNAL"
      },
      "title": "Cisco IOS XR Software Multi-Instance Intermediate System-to-Intermediate System Denial of Service Vulnerability"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
    "assignerShortName": "cisco",
    "cveId": "CVE-2026-20074",
    "datePublished": "2026-03-11T16:31:14.712Z",
    "dateReserved": "2025-10-08T11:59:15.362Z",
    "dateUpdated": "2026-03-11T17:20:21.640Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-95M8-QGXC-HCQX

CVE-2026-20074 (GCVE-0-2026-20074)

Tags

Sightings

Nomenclature