Vulnerability-Lookup

GHSA-VGPF-3M99-Q785

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

Details

This vulnerability is due to the corruption of packets in specific cases when an EPNI Aligner interrupt is triggered while an affected device is experiencing heavy transit traffic. An attacker could exploit this vulnerability by sending a continuous flow of crafted packets to an interface of the affected device. A successful exploit could allow the attacker to cause persistent, heavy packet loss, resulting in a denial of service (DoS) condition. Note: If active exploitation of this vulnerability is suspected, contact the Cisco Technical Assistance Center (TAC) or your contracted maintenance provider. Cisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates. This change was made because the affected device operates within a critical network segment where compromise could lead to significant disruption or exposure, thereby elevating the overall risk beyond the base technical severity.

Severity

6.8 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-20118"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-460"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-11T17:16:56Z",
    "severity": "MODERATE"
  },
  "details": "A vulnerability in the handling of an Egress Packet Network Interface (EPNI) Aligner interrupt in Cisco IOS XR Software for Cisco Network Convergence System (NCS) 5500 Series with NC57 line cards and Cisco NCS 5700 Routers and Cisco IOS XR Software for Third Party Software could allow an unauthenticated, remote attacker to cause the network processing unit (NPU) and ASIC to stop processing, preventing traffic from traversing the interface.\n\nThis vulnerability is due to the corruption of packets in specific cases when an EPNI Aligner interrupt is triggered while an affected device is experiencing heavy transit traffic. An attacker could exploit this vulnerability by sending a continuous flow of crafted packets to an interface of the affected device. A successful exploit could allow the attacker to cause persistent, heavy packet loss, resulting in a denial of service (DoS) condition.\nNote: If active exploitation of this vulnerability is suspected, contact the Cisco Technical Assistance Center (TAC) or your contracted maintenance provider.\nCisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates. This change was made because the affected device operates within a critical network segment where compromise could lead to significant disruption or exposure, thereby elevating the overall risk beyond the base technical severity.",
  "id": "GHSA-vgpf-3m99-q785",
  "modified": "2026-03-11T18:30:33Z",
  "published": "2026-03-11T18:30:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20118"
    },
    {
      "type": "WEB",
      "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xrncs-epni-int-dos-TWMffUsN"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-20118 (GCVE-0-2026-20118)

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

Title

Cisco IOS-XR NCS 5500 and NCS 5700 Egress Packet Network Interfaces Aligner Interrupt Denial of Service Vulnerability

Summary

A vulnerability in the handling of an Egress Packet Network Interface (EPNI) Aligner interrupt in Cisco IOS XR Software for Cisco Network Convergence System (NCS) 5500 Series with NC57 line cards and Cisco NCS 5700 Routers and Cisco IOS XR Software for Third Party Software could allow an unauthenticated, remote attacker to cause the network processing unit (NPU) and ASIC to stop processing, preventing traffic from traversing the interface. This vulnerability is due to the corruption of packets in specific cases when an EPNI Aligner interrupt is triggered while an affected device is experiencing heavy transit traffic. An attacker could exploit this vulnerability by sending a continuous flow of crafted packets to an interface of the affected device. A successful exploit could allow the attacker to cause persistent, heavy packet loss, resulting in a denial of service (DoS) condition. Note: If active exploitation of this vulnerability is suspected, contact the Cisco Technical Assistance Center (TAC) or your contracted maintenance provider. Cisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates. This change was made because the affected device operates within a critical network segment where compromise could lead to significant disruption or exposure, thereby elevating the overall risk beyond the base technical severity.

Severity

6.8 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-03-11 17:05 UTC

CWE

CWE-460 - Improper Cleanup on Thrown Exception

Assigner

cisco CNA under the mitre root

CNA scorecard C 66/100 over 431 records in the last 180 days details

References

1 reference

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

Impacted products

1 product

Vendor	Product	Version
Cisco	Cisco IOS XR Software	Affected: 7.9.1 Affected: 7.10.1 Affected: 7.9.2 Affected: 7.11.1 Affected: 7.10.2 Affected: 24.1.1 Affected: 7.11.2 Affected: 24.2.1 Affected: 24.1.2 Affected: 24.3.1 Affected: 24.4.1 Affected: 24.2.11 Affected: 24.2.2 Affected: 7.11.21 Affected: 24.2.20 Affected: 24.3.2 Affected: 25.1.1 Affected: 24.3.20 Affected: 24.4.2 Affected: 25.1.2 Affected: 24.3.30 Affected: 24.4.30 Affected: 24.2.21

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-20118",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-11T17:05:28.107036Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-11T17:20:21.023Z",
          "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": "7.9.1"
            },
            {
              "status": "affected",
              "version": "7.10.1"
            },
            {
              "status": "affected",
              "version": "7.9.2"
            },
            {
              "status": "affected",
              "version": "7.11.1"
            },
            {
              "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": "24.3.1"
            },
            {
              "status": "affected",
              "version": "24.4.1"
            },
            {
              "status": "affected",
              "version": "24.2.11"
            },
            {
              "status": "affected",
              "version": "24.2.2"
            },
            {
              "status": "affected",
              "version": "7.11.21"
            },
            {
              "status": "affected",
              "version": "24.2.20"
            },
            {
              "status": "affected",
              "version": "24.3.2"
            },
            {
              "status": "affected",
              "version": "25.1.1"
            },
            {
              "status": "affected",
              "version": "24.3.20"
            },
            {
              "status": "affected",
              "version": "24.4.2"
            },
            {
              "status": "affected",
              "version": "25.1.2"
            },
            {
              "status": "affected",
              "version": "24.3.30"
            },
            {
              "status": "affected",
              "version": "24.4.30"
            },
            {
              "status": "affected",
              "version": "24.2.21"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "A vulnerability in the handling of an Egress Packet Network Interface (EPNI) Aligner interrupt in Cisco IOS XR Software for Cisco Network Convergence System (NCS) 5500 Series with NC57 line cards and Cisco NCS 5700 Routers and Cisco IOS XR Software for Third Party Software could allow an unauthenticated, remote attacker to cause the network processing unit (NPU) and ASIC to stop processing, preventing traffic from traversing the interface.\r\n\r\nThis vulnerability is due to the corruption of packets in specific cases when an EPNI Aligner interrupt is triggered while an affected device is experiencing heavy transit traffic. An attacker could exploit this vulnerability by sending a continuous flow of crafted packets to an interface of the affected device. A successful exploit could allow the attacker to cause persistent, heavy packet loss, resulting in a denial of service (DoS) condition.\r\nNote: If active exploitation of this vulnerability is suspected, contact the Cisco Technical Assistance Center (TAC) or your contracted maintenance provider.\r\nCisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates. This change was made because the affected device operates within a critical network segment where compromise could lead to significant disruption or exposure, thereby elevating the overall risk beyond the base technical severity."
        }
      ],
      "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": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 6.8,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "cvssV3_1"
        }
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      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-460",
              "description": "Improper Cleanup on Thrown Exception",
              "lang": "en",
              "type": "cwe"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-11T16:31:32.117Z",
        "orgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
        "shortName": "cisco"
      },
      "references": [
        {
          "name": "cisco-sa-xrncs-epni-int-dos-TWMffUsN",
          "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xrncs-epni-int-dos-TWMffUsN"
        }
      ],
      "source": {
        "advisory": "cisco-sa-xrncs-epni-int-dos-TWMffUsN",
        "defects": [
          "CSCws66900"
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        "discovery": "EXTERNAL"
      },
      "title": "Cisco IOS-XR NCS 5500 and NCS 5700 Egress Packet Network Interfaces Aligner Interrupt Denial of Service Vulnerability"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
    "assignerShortName": "cisco",
    "cveId": "CVE-2026-20118",
    "datePublished": "2026-03-11T16:31:32.117Z",
    "dateReserved": "2025-10-08T11:59:15.376Z",
    "dateUpdated": "2026-03-11T17:20:21.023Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Publication & reservation Sightings KEV catalogs Other timestamps

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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.

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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