{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-19655", "assignerOrgId": "c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7", "state": "PUBLISHED", "assignerShortName": "Arista", "dateReserved": "2026-08-12T18:51:29.572Z", "datePublished": "2026-09-15T20:56:46.678Z", "dateUpdated": "2026-09-15T20:56:46.678Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7", "shortName": "Arista", "dateUpdated": "2026-09-15T20:56:46.678Z"}, "title": "On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay/snooping configured with the information option (Option 82), or with the DHCP server configured with match criteria based on the information option, an unauthent", "datePublic": "2026-09-09T20:56:00.000Z", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-20", "description": "CWE-20 Improper Input Validation", "type": "CWE"}]}], "impacts": [{"capecId": "CAPEC-153", "descriptions": [{"lang": "en", "value": "CAPEC-153 Input Data Manipulation"}]}], "affected": [{"vendor": "Arista Networks", "product": "EOS", "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 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", "CloudEOS", "cEOS-lab", "vEOS-lab", "CloudVision eXchange", "virtual or physical appliance"], "versions": [{"status": "affected", "version": "4.35.0", "lessThanOrEqual": "4.35.5M", "changes": [{"at": "4.35.6M", "status": "unaffected"}], "versionType": "custom"}, {"status": "affected", "version": "4.34.0", "lessThanOrEqual": "4.34.7.1M", "changes": [{"at": "4.34.8M", "status": "unaffected"}], "versionType": "custom"}, {"status": "affected", "version": "4.33.0", "lessThanOrEqual": "4.33.9M", "changes": [{"at": "4.33.10M", "status": "unaffected"}], "versionType": "custom"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay/snooping configured with the information option (Option 82), or with the DHCP server configured with match criteria based on the information option, an unauthenticated attacker connected to a client-facing VLAN(s) where the relay is configured can send a specially crafted packet that causes the DHCP Relay service to restart.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay/snooping configured with the information option (Option 82), or with the DHCP server configured with match criteria based on the information option, an unauthenticated attacker connected to a client-facing VLAN(s) where the relay is configured can send a specially crafted packet that causes the DHCP Relay service to restart.</p>"}]}], "references": [{"url": "https://www.arista.com/en/support/advisories-notices/security-advisory/24711-security-advisory-0155", "tags": ["vendor-advisory"]}], "configurations": [{"lang": "en", "value": "In order to be vulnerable to CVE-2026-19655, any of the following conditions must be met:\n\n\n\n1. Configure \"ip dhcp relay\" with the \"information option\" (Option 82) and at least one helper-address on an interface:\n\n\n\ninterface Vlan100\n ip helper-address 1.1.1.2\n ip dhcp relay information option\n\n\n\n2. Configure \"ip dhcp snooping\" with the \"information option\":\n\n\n\nswitch#show running-config | grep snooping\nip dhcp snooping\nip dhcp snooping information option\nip dhcp snooping vlan 100\n\n\n\n3. The DHCP server uses match criteria based on the information option, configured with \"information option arista-switch\" commands:\n\n\n\ndhcp server\n client class ipv4 definition name\n assignments\n private-option 224 always-send type string data \"data1\"\n !\n match\n information option arista-switch Ethernet55/1 vlan 100\n !\n subnet 1.0.0.0/24\n range 1.0.0.1 1.0.0.5\ninterface Vlan10\n dhcp server ipv4", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>In order to be vulnerable to CVE-2026-19655, any of the following conditions must be met:</p><p>1. Configure \"ip dhcp relay\" with the \"information option\" (Option 82) and at least one helper-address on an interface:</p><pre>interface Vlan100\n ip helper-address 1.1.1.2\n ip dhcp relay information option</pre><p>2. Configure \"ip dhcp snooping\" with the \"information option\":</p><pre>switch#show running-config | grep snooping\nip dhcp snooping\nip dhcp snooping information option\nip dhcp snooping vlan 100</pre><p>3. The DHCP server uses match criteria based on the information option, configured with \"information option arista-switch\" commands:</p><pre>dhcp server\n client class ipv4 definition name\n assignments\n private-option 224 always-send type string data \"data1\"\n !\n match\n information option arista-switch Ethernet55/1 vlan 100\n !\n subnet 1.0.0.0/24\n range 1.0.0.1 1.0.0.5\ninterface Vlan10\n dhcp server ipv4</pre>"}]}], "workarounds": [{"lang": "en", "value": "There is no workaround known for this issue.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>There is no workaround known for this issue.</p>"}]}], "solutions": [{"lang": "en", "value": "The recommended resolution is to upgrade to a remediated software version at your earliest convenience. CVE-2026-19655 has been fixed in the following releases:\n\n * 4.35.6M and later releases in the 4.35.x train\n * 4.34.8M and later releases in the 4.34.x train\n * 4.33.10M and later releases in the 4.33.x train", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>The recommended resolution is to upgrade to a remediated software version at your earliest convenience. CVE-2026-19655 has been fixed in the following releases:</p><ul><li>4.35.6M and later releases in the 4.35.x train</li><li>4.34.8M and later releases in the 4.34.x train</li><li>4.33.10M and later releases in the 4.33.x train</li></ul>"}]}], "credits": [{"lang": "en", "value": "This issue was discovered internally by Arista.", "type": "finder"}], "source": {"defect": ["1770194"], "advisory": "155", "discovery": "INTERNAL"}, "x_generator": {"engine": "Vulnogram 1.0.5"}, "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "attackVector": "ADJACENT_NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH", "baseSeverity": "MEDIUM", "baseScore": 6.5, "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}}, {"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "ADJACENT", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "HIGH", "baseScore": 7.1, "vectorString": "CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}}]}}}

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{"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 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", "CloudEOS", "cEOS-lab", "vEOS-lab", "CloudVision eXchange", "virtual or physical appliance"], "product": "EOS", "vendor": "Arista Networks", "versions": [{"changes": [{"at": "4.35.6M", "status": "unaffected"}], "lessThanOrEqual": "4.35.5M", "status": "affected", "version": "4.35.0", "versionType": "custom"}, {"changes": [{"at": "4.34.8M", "status": "unaffected"}], "lessThanOrEqual": "4.34.7.1M", "status": "affected", "version": "4.34.0", "versionType": "custom"}, {"changes": [{"at": "4.33.10M", "status": "unaffected"}], "lessThanOrEqual": "4.33.9M", "status": "affected", "version": "4.33.0", "versionType": "custom"}]}], "source": "psirt@arista.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay/snooping configured with the information option (Option 82), or with the DHCP server configured with match criteria based on the information option, an unauthenticated attacker connected to a client-facing VLAN(s) where the relay is configured can send a specially crafted packet that causes the DHCP Relay service to restart."}], "id": "CVE-2026-19655", "lastModified": "2026-09-15T21:16:36.380", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "psirt@arista.com", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "ADJACENT", "availabilityRequirement": "NOT_DEFINED", "baseScore": 7.1, "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:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "psirt@arista.com", "type": "Secondary"}]}, "published": "2026-09-15T21:16:36.380", "references": [{"source": "psirt@arista.com", "url": "https://www.arista.com/en/support/advisories-notices/security-advisory/24711-security-advisory-0155"}], "sourceIdentifier": "psirt@arista.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-20"}], "source": "psirt@arista.com", "type": "Secondary"}]}

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