{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-121290", "assignerOrgId": "c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7", "state": "PUBLISHED", "assignerShortName": "Arista", "dateReserved": "2026-11-03T11:21:01.892Z", "datePublished": "2026-11-10T20:09:57.273Z", "dateUpdated": "2026-11-10T20:09:57.273Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7", "shortName": "Arista", "dateUpdated": "2026-11-10T20:09:57.273Z"}, "title": "Security Advisory 0209", "descriptions": [{"lang": "en", "value": "On affected platforms running Arista EOS with Border Gateway Protocol (BGP) changing the BGP listen port from its default value disables default protective Access Control List (ACL) rules against unexpected BGP peering attempts."}], "affected": [{"vendor": "Arista Networks", "product": "EOS", "defaultStatus": "unaffected", "versions": [{"version": "4.36.0F", "status": "affected", "versionType": "custom", "lessThanOrEqual": "4.36.2F"}, {"version": "4.35.0F", "status": "affected", "versionType": "custom", "lessThanOrEqual": "4.35.6M"}, {"version": "4.34.0F", "status": "affected", "versionType": "custom", "lessThanOrEqual": "4.34.8M"}, {"version": "4.33.0F", "status": "affected", "versionType": "custom", "lessThanOrEqual": "4.33.10M"}, {"version": "4.32.0F", "status": "affected", "versionType": "custom", "lessThan": "4.33.0F"}, {"version": "1.0.0", "status": "affected", "versionType": "custom", "lessThan": "4.32.0F"}], "platforms": ["710 Series", "720D Series", "720XP/722XPM Series", "750X Series", "7010TX Series", "7020R/R4 Series", "7130 Series running EOS", "7170 Series", "7050X3/X4 Series", "7060X/X2/X4/X5/X6/XE7 Series", "7260X/X3 Series", "7280R/R2/R3/R4 Series", "7300X/X3 Series", "7320X Series", "7358X4 Series", "7368X4 Series", "7388X5 Series", "7500R/R2/R3 Series", "7800R3/R4 Series", "7700R4 Series", "AWE 5000 Series", "AWE 7200R Series", "ZTX-7200 Series", "CloudEOS", "cEOS-lab", "vEOS-lab", "CloudVision eXchange, virtual or physical appliance"]}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H", "baseScore": 8.2, "baseSeverity": "HIGH"}}, {"cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N", "baseScore": 8.3, "baseSeverity": "HIGH"}}], "references": [{"url": "https://www.arista.com/en/support/advisories-notices/security-advisory/25031-security-advisory-0209", "tags": ["vendor-advisory"]}], "source": {"defects": ["1977472"], "advisory": "Security Advisory 0209", "discovery": "INTERNAL"}, "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-420", "description": "CWE-420 Unprotected Alternate Channel"}]}], "configurations": [{"lang": "en", "value": "switch>show running-config section bgp | include listen-port\n bgp transport listen-port 1179\n\nswitch>show running-config all | inc service routing protocols\nservice routing protocols model multi-agent", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<pre>switch>show running-config section bgp | include listen-port\n bgp transport listen-port 1179\n\nswitch>show running-config all | inc service routing protocols\nservice routing protocols model multi-agent</pre>"}]}], "workarounds": [{"lang": "en", "value": "router bgp <asn>\n no bgp transport listen-port\n\nIf the non-default listen port must be retained, the required modifications to the control plane ACL (to allow the non-default listen port to be reached) should be made in such a manner to provide the desired protection \u2014 only allowing TCP connections using the non-default listen port when the remote IP address is an expected one, and if applicable, when the TTL value is within the expected range.", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<pre>router bgp <asn>\n no bgp transport listen-port\n\nIf the non-default listen port must be retained, the required modifications to the control plane ACL (to allow the non-default listen port to be reached) should be made in such a manner to provide the desired protection \u2014 only allowing TCP connections using the non-default listen port when the remote IP address is an expected one, and if applicable, when the TTL value is within the expected range.</pre>"}]}], "impacts": [{"capecId": "CAPEC-212", "descriptions": [{"lang": "en", "value": "CAPEC-212 Functionality Misuse"}]}]}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "platforms": ["710 Series", "720D Series", "720XP/722XPM Series", "750X Series", "7010TX Series", "7020R/R4 Series", "7130 Series running EOS", "7170 Series", "7050X3/X4 Series", "7060X/X2/X4/X5/X6/XE7 Series", "7260X/X3 Series", "7280R/R2/R3/R4 Series", "7300X/X3 Series", "7320X Series", "7358X4 Series", "7368X4 Series", "7388X5 Series", "7500R/R2/R3 Series", "7800R3/R4 Series", "7700R4 Series", "AWE 5000 Series", "AWE 7200R Series", "ZTX-7200 Series", "CloudEOS", "cEOS-lab", "vEOS-lab", "CloudVision eXchange, virtual or physical appliance"], "product": "EOS", "vendor": "Arista Networks", "versions": [{"lessThanOrEqual": "4.36.2F", "status": "affected", "version": "4.36.0F", "versionType": "custom"}, {"lessThanOrEqual": "4.35.6M", "status": "affected", "version": "4.35.0F", "versionType": "custom"}, {"lessThanOrEqual": "4.34.8M", "status": "affected", "version": "4.34.0F", "versionType": "custom"}, {"lessThanOrEqual": "4.33.10M", "status": "affected", "version": "4.33.0F", "versionType": "custom"}, {"lessThan": "4.33.0F", "status": "affected", "version": "4.32.0F", "versionType": "custom"}, {"lessThan": "4.32.0F", "status": "affected", "version": "1.0.0", "versionType": "custom"}]}], "source": "psirt@arista.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "On affected platforms running Arista EOS with Border Gateway Protocol (BGP) changing the BGP listen port from its default value disables default protective Access Control List (ACL) rules against unexpected BGP peering attempts."}], "id": "CVE-2026-121290", "lastModified": "2026-11-10T20:18:54.447", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.2, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 4.2, "source": "psirt@arista.com", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.3, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "psirt@arista.com", "type": "Secondary"}]}, "published": "2026-11-10T20:18:54.447", "references": [{"source": "psirt@arista.com", "url": "https://www.arista.com/en/support/advisories-notices/security-advisory/25031-security-advisory-0209"}], "sourceIdentifier": "psirt@arista.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-420"}], "source": "psirt@arista.com", "type": "Secondary"}]}

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{}