{
  "document": {
    "acknowledgments": [
      {
        "summary": "This vulnerability was found during internal security testing."
      }
    ],
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "notes": [
      {
        "category": "summary",
        "text": "A vulnerability in the implementation of the Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to the incorrect processing of a BGP update message that contains specific EVPN attributes. An attacker could exploit this vulnerability by sending a BGP update message that contains specific EVPN attributes. To exploit this vulnerability, an attacker must control a BGP speaker that has an established trusted peer connection to an affected device that is configured with the address family L2VPN EVPN to receive and process the update message. This vulnerability cannot be exploited by any data that is initiated by clients on the Layer 2 network or by peers that are not configured to accept the L2VPN EVPN address family. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition.\r\n\r\nThe Cisco implementation of BGP accepts incoming BGP updates only from explicitly defined peers. For this vulnerability to be exploited, the malicious BGP update message must either come from a configured, valid BGP peer or be injected by the attacker into the affected BGP network on an existing, valid TCP connection to a BGP peer.\r\n\r\nCisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.\r\n\r\n\r\n\r\nThis advisory is part of the April 2022 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: April 2022 Cisco IOS XR Software Security Advisory Bundled Publication [\"https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74835\"].",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "At the time of publication, this vulnerability affected Cisco devices if they were running a vulnerable release of Cisco IOS XR Software and had BGP configured with at least one peer that was configured with the address family L2VPN EVPN.\r\n\r\nFor information about which Cisco software releases were vulnerable at the time of publication, see the Fixed Software [\"#fs\"] section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.\r\n\r\nDetermine Whether the Device is Configured for BGP\r\n\r\nTo determine whether the device is configured for BGP, use the show running-config router bgp EXEC CLI command. If the router is configured for BGP, this command will return output, as shown in the following example:\r\n\r\n\r\n# show running-config router bgp\r\nrouter bgp 65536...\r\n\r\nDetermine Whether the Device has L2VPN EVPN Neighbors Configured\r\n\r\nTo determine whether the device has any neighbors that are configured for the L2VPN EVPN address family, use the show running-config router bgp AS-number EXEC CLI command. The following example shows the partial output of the show running-config router bgp AS-number command on a device that has the L2VPN EVPN address family configured:\r\n\r\n\r\n# show running-config router bgp 65536\r\nrouter bgp 65536address-family l2vpn evpn..\r\nneighbor-group example\r\naddress-family l2vpn evpn.\r\n neighbor 2001:DB8::1\r\n  use neighbor-group example\r\n !",
        "title": "Vulnerable Products"
      },
      {
        "category": "general",
        "text": "Only products listed in the Vulnerable Products [\"#vp\"] section of this advisory are known to be affected by this vulnerability.\r\n\r\nCisco has confirmed that this vulnerability does not affect the following Cisco products:\r\n\r\nIOS Software\r\nIOS XE Software\r\nNX-OS Software",
        "title": "Products Confirmed Not Vulnerable"
      },
      {
        "category": "general",
        "text": "EVPN is a next-generation solution that provides Ethernet multipoint services over MPLS networks. Customers can learn more about EVPN and configuration options in guides, such as L2VPN and Ethernet Services Configuration Guide for Cisco ASR 9000 Series Routers [\"https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r7-0/lxvpn/configuration/guide/b-l2vpn-cg-asr9000-70x/b-l2vpn-cg-asr9000-70x_chapter_01011.html\"], and in guides for other platforms that support this feature.",
        "title": "Details"
      },
      {
        "category": "general",
        "text": "There are no workarounds that address this vulnerability.",
        "title": "Workarounds"
      },
      {
        "category": "general",
        "text": "When considering software upgrades [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"], customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page [\"https://www.cisco.com/go/psirt\"], to determine exposure and a complete upgrade solution.\r\n\r\nIn all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.\r\n      Fixed Releases\r\nAt the time of publication, the release information in the following table(s) was accurate. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.\r\n\r\nThe left column lists Cisco software releases, and the right column indicates whether a release was affected by the vulnerability described in this advisory and which release included the fix for this vulnerability.\r\n        Cisco IOS XR Software Release  First Fixed Release           6.5 and earlier  Not vulnerable.      6.6  Vulnerable; migrate to a fixed release.      6.7  Vulnerable; migrate to a fixed release.      6.8  6.8.2      7.0  Vulnerable; migrate to a fixed release.      7.1  Vulnerable; migrate to a fixed release.      7.2  Vulnerable; migrate to a fixed release.      7.3  7.3.2      7.4  7.4.2      7.5 and later  Not affected.\r\nAt the time of publication, Cisco had released the following SMUs to address this vulnerability. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information, including SMU availability. Customers who require SMUs for platforms or releases that are not listed are advised to contact their support organization.\r\n        Cisco IOS XR Software Release  Platform  SMU Name          7.1.2  NCS5500  ncs5500-7.1.2.CSCvz26082      7.4.15  IOSXRWBD  iosxrwbd-7.4.15.CSCvz26082      7.4.16  IOSXRWBD  iosxrwbd-7.4.16.CSCvz26082\r\nThe Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.",
        "title": "Fixed Software"
      },
      {
        "category": "general",
        "text": "To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html\"]. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.",
        "title": "Vulnerability Policy"
      },
      {
        "category": "general",
        "text": "The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.",
        "title": "Exploitation and Public Announcements"
      },
      {
        "category": "general",
        "text": "This vulnerability was found during internal security testing.",
        "title": "Source"
      },
      {
        "category": "legal_disclaimer",
        "text": "THIS DOCUMENT IS PROVIDED ON AN \"AS IS\" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.\r\n\r\nA standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products.",
        "title": "Legal Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "psirt@cisco.com",
      "issuing_authority": "Cisco PSIRT",
      "name": "Cisco",
      "namespace": "https://wwww.cisco.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "Cisco IOS XR Software Border Gateway Protocol Ethernet VPN Denial of Service Vulnerability",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bgpevpn-zWTRtPBb"
      },
      {
        "category": "external",
        "summary": "Cisco Event Response: April 2022 Cisco IOS XR Software Security Advisory Bundled Publication",
        "url": "https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74835"
      },
      {
        "category": "external",
        "summary": "Cisco Security Vulnerability Policy",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
      },
      {
        "category": "external",
        "summary": "L2VPN and Ethernet Services Configuration Guide for Cisco\u0026nbsp;ASR 9000 Series Routers",
        "url": "https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r7-0/lxvpn/configuration/guide/b-l2vpn-cg-asr9000-70x/b-l2vpn-cg-asr9000-70x_chapter_01011.html"
      },
      {
        "category": "external",
        "summary": "considering software upgrades",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"
      },
      {
        "category": "external",
        "summary": "Cisco\u0026nbsp;Security Advisories page",
        "url": "https://www.cisco.com/go/psirt"
      }
    ],
    "title": "Cisco IOS XR Software Border Gateway Protocol Ethernet VPN Denial of Service Vulnerability",
    "tracking": {
      "current_release_date": "2022-04-19T14:12:27+00:00",
      "generator": {
        "date": "2024-05-10T23:13:57+00:00",
        "engine": {
          "name": "TVCE"
        }
      },
      "id": "cisco-sa-bgpevpn-zWTRtPBb",
      "initial_release_date": "2022-04-13T16:00:00+00:00",
      "revision_history": [
        {
          "date": "2022-04-13T15:41:29+00:00",
          "number": "1.0.0",
          "summary": "Initial public release."
        },
        {
          "date": "2022-04-19T14:12:27+00:00",
          "number": "1.1.0",
          "summary": "Added 6.8.2 as a fixed release."
        }
      ],
      "status": "final",
      "version": "1.1.0"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "category": "product_family",
            "name": "Cisco IOS XR Software",
            "product": {
              "name": "Cisco IOS XR Software ",
              "product_id": "CSAFPID-5834"
            }
          }
        ],
        "category": "vendor",
        "name": "Cisco"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2022-20758",
      "ids": [
        {
          "system_name": "Cisco Bug ID",
          "text": "CSCvz26082"
        }
      ],
      "notes": [
        {
          "category": "other",
          "text": "Complete.",
          "title": "Affected Product Comprehensiveness"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-5834"
        ]
      },
      "release_date": "2022-04-13T16:00:00+00:00",
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Cisco has released software updates that address this vulnerability.",
          "product_ids": [
            "CSAFPID-5834"
          ],
          "url": "https://software.cisco.com"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 6.8,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-5834"
          ]
        }
      ],
      "title": "Cisco IOS XR Software BGP EVPN Denial of Service Vulnerability"
    }
  ]
}