{
  "document": {
    "acknowledgments": [
      {
        "summary": "This vulnerability was found during the resolution of a Cisco Technical Assistance Center (TAC) support case."
      }
    ],
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "notes": [
      {
        "category": "summary",
        "text": "A vulnerability in the access control list (ACL) programming of Cisco IOS XE Software for Cisco Catalyst 9500X and 9600X Series Switches could allow an unauthenticated, remote attacker to bypass a configured ACL on an affected device.\r\n\r\nThis vulnerability is due to the flooding of traffic from an unlearned MAC address on a switch virtual interface (SVI) that has an egress ACL applied. An attacker could exploit this vulnerability by causing the VLAN to flush its MAC address table. This condition can also occur if the MAC address table is full. A successful exploit could allow the attacker to bypass an egress ACL on an affected device.\r\n\r\nCisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.\r\n\r\n\r\n\r\nThis advisory is part of the September 2025 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2025 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication [\"https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75296\"].",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "At the time of publication, this vulnerability affected Cisco Catalyst 9500X and 9600X Series Switches if they were running a vulnerable release of Cisco IOS XE Software and had an egress ACL configured on an SVI.\r\n\r\nFor information about which Cisco software releases are vulnerable, see the Fixed Software [\"#fs\"] section of this advisory.\r\n  Determine the Device Configuration\r\nTo determine whether an outbound ACL is configured on an SVI, use the show running-config | include interface Vlan|out$ command. The following example shows output on a device that has an egress ACL configured on an SVI:\r\n\r\n\r\nSwitch# Router# show running-config | include interface Vlan|out$\r\ninterface Vlan1\r\n ip access-group 101 out\r\nSwitch#",
        "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\nCatalyst 9500 Series Switches\r\nCatalyst 9600 Series Switches\r\nIOS Software\r\nIOS XR Software\r\nNX-OS Software",
        "title": "Products Confirmed Not Vulnerable"
      },
      {
        "category": "general",
        "text": "There is a workaround that addresses this vulnerability. Egress ACLs can be converted to ingress ACLs. However, depending on how many interfaces are configured with egress ACLs, the configuration changes required could be extensive.\r\n\r\nWhile this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.",
        "title": "Workarounds"
      },
      {
        "category": "general",
        "text": "Cisco considers any workarounds and mitigations to be temporary solutions until an upgrade to a fixed software release is available. To fully remediate this vulnerability and avoid future exposure as described in this advisory, Cisco strongly recommends that customers upgrade to the fixed software indicated in this advisory.\r\n        Cisco IOS and IOS XE Software\r\nTo help customers determine their exposure to vulnerabilities in Cisco IOS and IOS XE Software, Cisco provides the Cisco Software Checker [\"https://sec.cloudapps.cisco.com/security/center/softwarechecker.x\"]. This tool identifies any Cisco security advisories that impact a specific software release and the earliest release that fixes the vulnerabilities that are described in each advisory (\u201cFirst Fixed\u201d). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities that are described in all the advisories that the Software Checker identifies (\u201cCombined First Fixed\u201d).\r\n\r\nTo use the tool, go to the Cisco Software Checker [\"https://sec.cloudapps.cisco.com/security/center/softwarechecker.x\"] page and follow the instructions. Alternatively, use the following form to determine whether a release is affected by any Cisco Security Advisory. To use the form, follow these steps:\r\n\r\nChoose which advisories the tool will search\u2014only this advisory, only advisories with a Critical or High Security Impact Rating (SIR) [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#asr\"], or all advisories.\r\nEnter a release number\u2014for example, 15.9(3)M2 or 17.3.3.\r\nClick Check.\r\n\r\n       Only this advisory  All Critical and High advisories  All advisories",
        "title": "Fixed Software"
      },
      {
        "category": "general",
        "text": "To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy [\"http://www.cisco.com/web/about/security/psirt/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 Product Security Incident Response Team (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 the resolution of a Cisco Technical Assistance Center (TAC) support case.",
        "title": "Source"
      },
      {
        "category": "legal_disclaimer",
        "text": "SOFTWARE DOWNLOADS AND TECHNICAL SUPPORT\r\n\r\nThe Cisco Support and Downloads [\"https://www.cisco.com/c/en/us/support/index.html\"] page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool. Please note that customers may download only software that was procured from Cisco directly or through a Cisco authorized reseller or partner and for which the license is still valid.\r\n\r\nCustomers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC) [\"https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html\"]. Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.\r\n\r\nWhen considering software upgrades [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"], customers are advised to regularly consult the advisories [\"https://www.cisco.com/go/psirt\"] for the relevant Cisco products to determine exposure and a complete upgrade solution. In 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) [\"https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html\"] or their contracted maintenance providers.\r\n    LEGAL DISCLAIMER DETAILS\r\n\r\nCISCO DOES NOT MAKE ANY EXPRESS OR IMPLIED GUARANTEES OR WARRANTIES OF ANY KIND, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, CISCO DOES NOT GUARANTEE THE ACCURACY OR COMPLETENESS OF THIS INFORMATION. THIS DOCUMENT IS PROVIDED ON AN \"AS IS\" BASIS. 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\nCopies or summaries of the information contained in this Security Advisory may lack important information or contain factual errors. Customers are advised to visit the Cisco Security Advisories [\"https://www.cisco.com/go/psirt\"] page for the most recent version of this Security Advisory. The Cisco Product Security Incident Response Team (PSIRT) assesses only the affected and fixed release information that is documented in this advisory. See the Cisco Security Vulnerability Policy [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"] for more information.",
        "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 XE Software on Cisco Catalyst 9500X and 9600X Series Switches Virtual Interface Access Control List Bypass Vulnerability",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cat9k-acl-L4K7VXgD"
      },
      {
        "category": "external",
        "summary": "Cisco Event Response: September 2025 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication",
        "url": "https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75296"
      },
      {
        "category": "external",
        "summary": "Cisco Security Vulnerability Policy",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
      },
      {
        "category": "external",
        "summary": "Cisco Software Checker",
        "url": "https://sec.cloudapps.cisco.com/security/center/softwarechecker.x"
      },
      {
        "category": "external",
        "summary": "Security Impact Rating (SIR)",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#asr"
      },
      {
        "category": "external",
        "summary": "Security Vulnerability Policy",
        "url": "http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"
      },
      {
        "category": "external",
        "summary": "Cisco Support and Downloads",
        "url": "https://www.cisco.com/c/en/us/support/index.html"
      },
      {
        "category": "external",
        "summary": "Cisco Technical Assistance Center (TAC)",
        "url": "https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"
      },
      {
        "category": "external",
        "summary": "considering software upgrades",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"
      },
      {
        "category": "external",
        "summary": "the advisories",
        "url": "https://www.cisco.com/go/psirt"
      }
    ],
    "title": "Cisco IOS XE Software on Cisco Catalyst 9500X and 9600X Series Switches Virtual Interface Access Control List Bypass Vulnerability",
    "tracking": {
      "current_release_date": "2025-09-24T16:00:00+00:00",
      "generator": {
        "date": "2025-09-24T16:06:55+00:00",
        "engine": {
          "name": "TVCE"
        }
      },
      "id": "cisco-sa-cat9k-acl-L4K7VXgD",
      "initial_release_date": "2025-09-24T16:00:00+00:00",
      "revision_history": [
        {
          "date": "2025-09-24T16:06:19+00:00",
          "number": "1.0.0",
          "summary": "Initial public release."
        }
      ],
      "status": "final",
      "version": "1.0.0"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.7.1",
                    "product": {
                      "name": "17.7.1",
                      "product_id": "CSAFPID-277357"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.7"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.10.1",
                    "product": {
                      "name": "17.10.1",
                      "product_id": "CSAFPID-278018"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.10.1b",
                    "product": {
                      "name": "17.10.1b",
                      "product_id": "CSAFPID-292650"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.10"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.8.1",
                    "product": {
                      "name": "17.8.1",
                      "product_id": "CSAFPID-278023"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.8"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.9.1",
                    "product": {
                      "name": "17.9.1",
                      "product_id": "CSAFPID-278025"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.2",
                    "product": {
                      "name": "17.9.2",
                      "product_id": "CSAFPID-288221"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.3",
                    "product": {
                      "name": "17.9.3",
                      "product_id": "CSAFPID-290674"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.4",
                    "product": {
                      "name": "17.9.4",
                      "product_id": "CSAFPID-295412"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.5",
                    "product": {
                      "name": "17.9.5",
                      "product_id": "CSAFPID-300263"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.4a",
                    "product": {
                      "name": "17.9.4a",
                      "product_id": "CSAFPID-300845"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.6",
                    "product": {
                      "name": "17.9.6",
                      "product_id": "CSAFPID-301723"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.6a",
                    "product": {
                      "name": "17.9.6a",
                      "product_id": "CSAFPID-302891"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.6b",
                    "product": {
                      "name": "17.9.6b",
                      "product_id": "CSAFPID-303015"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.7",
                    "product": {
                      "name": "17.9.7",
                      "product_id": "CSAFPID-303042"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.9"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.11.1",
                    "product": {
                      "name": "17.11.1",
                      "product_id": "CSAFPID-286799"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.11"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.12.1",
                    "product": {
                      "name": "17.12.1",
                      "product_id": "CSAFPID-286801"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.12.2",
                    "product": {
                      "name": "17.12.2",
                      "product_id": "CSAFPID-300834"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.12.3",
                    "product": {
                      "name": "17.12.3",
                      "product_id": "CSAFPID-300936"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.12.4",
                    "product": {
                      "name": "17.12.4",
                      "product_id": "CSAFPID-301716"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.12.5",
                    "product": {
                      "name": "17.12.5",
                      "product_id": "CSAFPID-303034"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.12"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.13.1",
                    "product": {
                      "name": "17.13.1",
                      "product_id": "CSAFPID-295359"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.13"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.14.1",
                    "product": {
                      "name": "17.14.1",
                      "product_id": "CSAFPID-295361"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.14"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.15.1",
                    "product": {
                      "name": "17.15.1",
                      "product_id": "CSAFPID-300938"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.15.2",
                    "product": {
                      "name": "17.15.2",
                      "product_id": "CSAFPID-302782"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.15.3",
                    "product": {
                      "name": "17.15.3",
                      "product_id": "CSAFPID-303045"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.15.2b",
                    "product": {
                      "name": "17.15.2b",
                      "product_id": "CSAFPID-303311"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.15"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.16.1",
                    "product": {
                      "name": "17.16.1",
                      "product_id": "CSAFPID-301219"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.16"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.17.1",
                    "product": {
                      "name": "17.17.1",
                      "product_id": "CSAFPID-302626"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.17"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.18.0EFT",
                    "product": {
                      "name": "17.18.0EFT",
                      "product_id": "CSAFPID-305288"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.18EFT"
              }
            ],
            "category": "product_family",
            "name": "Cisco IOS XE Software"
          }
        ],
        "category": "vendor",
        "name": "Cisco"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2025-20316",
      "ids": [
        {
          "system_name": "Cisco Bug ID",
          "text": "CSCwo11541"
        }
      ],
      "notes": [
        {
          "category": "other",
          "text": "Complete.",
          "title": "Affected Product Comprehensiveness"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-277357",
          "CSAFPID-278018",
          "CSAFPID-278023",
          "CSAFPID-278025",
          "CSAFPID-286799",
          "CSAFPID-286801",
          "CSAFPID-288221",
          "CSAFPID-290674",
          "CSAFPID-292650",
          "CSAFPID-295359",
          "CSAFPID-295361",
          "CSAFPID-295412",
          "CSAFPID-300263",
          "CSAFPID-300834",
          "CSAFPID-300845",
          "CSAFPID-300936",
          "CSAFPID-300938",
          "CSAFPID-301219",
          "CSAFPID-301716",
          "CSAFPID-301723",
          "CSAFPID-302626",
          "CSAFPID-302782",
          "CSAFPID-302891",
          "CSAFPID-303015",
          "CSAFPID-303034",
          "CSAFPID-303042",
          "CSAFPID-303045",
          "CSAFPID-303311",
          "CSAFPID-305288"
        ]
      },
      "release_date": "2025-09-24T16:00:00+00:00",
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Cisco has released software updates that address this vulnerability.",
          "product_ids": [
            "CSAFPID-277357",
            "CSAFPID-278018",
            "CSAFPID-278023",
            "CSAFPID-278025",
            "CSAFPID-286799",
            "CSAFPID-286801",
            "CSAFPID-288221",
            "CSAFPID-290674",
            "CSAFPID-292650",
            "CSAFPID-295359",
            "CSAFPID-295361",
            "CSAFPID-295412",
            "CSAFPID-300263",
            "CSAFPID-300834",
            "CSAFPID-300845",
            "CSAFPID-300936",
            "CSAFPID-300938",
            "CSAFPID-301219",
            "CSAFPID-301716",
            "CSAFPID-301723",
            "CSAFPID-302626",
            "CSAFPID-302782",
            "CSAFPID-302891",
            "CSAFPID-303015",
            "CSAFPID-303034",
            "CSAFPID-303042",
            "CSAFPID-303045",
            "CSAFPID-303311",
            "CSAFPID-305288"
          ],
          "url": "https://software.cisco.com"
        },
        {
          "category": "workaround",
          "details": "There is a workaround that addresses this vulnerability. Egress ACLs can be converted to ingress ACLs. However, depending on how many interfaces are configured with egress ACLs, the configuration changes required could be extensive.\r\n\r\nWhile this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.",
          "product_ids": [
            "CSAFPID-277357",
            "CSAFPID-278018",
            "CSAFPID-278023",
            "CSAFPID-278025",
            "CSAFPID-286799",
            "CSAFPID-286801",
            "CSAFPID-288221",
            "CSAFPID-290674",
            "CSAFPID-292650",
            "CSAFPID-295359",
            "CSAFPID-295361",
            "CSAFPID-295412",
            "CSAFPID-300263",
            "CSAFPID-300834",
            "CSAFPID-300845",
            "CSAFPID-300936",
            "CSAFPID-300938",
            "CSAFPID-301219",
            "CSAFPID-301716",
            "CSAFPID-301723",
            "CSAFPID-302626",
            "CSAFPID-302782",
            "CSAFPID-302891",
            "CSAFPID-303015",
            "CSAFPID-303034",
            "CSAFPID-303042",
            "CSAFPID-303045",
            "CSAFPID-303311",
            "CSAFPID-305288"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-277357",
            "CSAFPID-278018",
            "CSAFPID-278023",
            "CSAFPID-278025",
            "CSAFPID-286799",
            "CSAFPID-286801",
            "CSAFPID-288221",
            "CSAFPID-290674",
            "CSAFPID-292650",
            "CSAFPID-295359",
            "CSAFPID-295361",
            "CSAFPID-295412",
            "CSAFPID-300263",
            "CSAFPID-300834",
            "CSAFPID-300845",
            "CSAFPID-300936",
            "CSAFPID-300938",
            "CSAFPID-301219",
            "CSAFPID-301716",
            "CSAFPID-301723",
            "CSAFPID-302626",
            "CSAFPID-302782",
            "CSAFPID-302891",
            "CSAFPID-303015",
            "CSAFPID-303034",
            "CSAFPID-303042",
            "CSAFPID-303045",
            "CSAFPID-303311",
            "CSAFPID-305288"
          ]
        }
      ],
      "title": "Cisco IOS XE Software on Cisco Catalyst 9500x and 9600x Access control List Bypass Vulnerbility"
    }
  ]
}