CVE-2026-73446

On affected platforms running Arista EOS with IS-IS configured on a broadcast interface, an unauthenticated attacker can send a crafted IS-IS Hello Protocol Data Unit (PDU) that causes the device to tear down an established IS-IS adjacency. This may result in traffic disruption and loss of IP reachability for prefixes advertised through that adjacency.

CVSS v3 7.4 HIGH

7.4^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 4.0

Attack Vector ADJACENT_NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope CHANGED

References

Link	Resource
https://www.arista.com/en/support/advisories-notices/security-advisory/24716-security-advisory-0160

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-16 00:17

Updated : 2026-09-16 00:17

NVD link : CVE-2026-73446

Mitre link : CVE-2026-73446

CVE.ORG link : CVE-2026-73446

JSON object : View

Products Affected

No product.

CWE

CWE-696

Incorrect Behavior Order

{"id": "CVE-2026-73446", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "psirt@arista.com", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 7.4, "attackVector": "ADJACENT_NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 4.0, "exploitabilityScore": 2.8}], "cvssMetricV40": [{"type": "Secondary", "source": "psirt@arista.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 7.0, "Automatable": "NOT_DEFINED", "attackVector": "ADJACENT", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "psirt@arista.com", "affectedData": [{"vendor": "Arista Networks", "product": "EOS", "versions": [{"status": "affected", "version": "4.36.0", "versionType": "custom", "lessThanOrEqual": "4.36.1F"}, {"status": "affected", "version": "4.35.0", "versionType": "custom", "lessThanOrEqual": "4.35.5M"}, {"status": "affected", "version": "4.34.0", "versionType": "custom", "lessThanOrEqual": "4.34.7.1M"}, {"status": "affected", "version": "4.33.0", "versionType": "custom", "lessThanOrEqual": "4.33.9M"}, {"status": "affected", "version": "4.32.0", "lessThan": "4.33.0F", "versionType": "custom"}, {"status": "affected", "version": "4.31.0", "lessThan": "4.32.0F", "versionType": "custom"}], "defaultStatus": "unaffected"}]}], "published": "2026-09-16T00:17:05.000", "references": [{"url": "https://www.arista.com/en/support/advisories-notices/security-advisory/24716-security-advisory-0160", "source": "psirt@arista.com"}], "vulnStatus": "Received", "weaknesses": [{"type": "Secondary", "source": "psirt@arista.com", "description": [{"lang": "en", "value": "CWE-696"}]}], "descriptions": [{"lang": "en", "value": "On affected platforms running Arista EOS with IS-IS configured on a broadcast interface, an unauthenticated attacker can send a crafted IS-IS Hello Protocol Data Unit (PDU) that causes the device to tear down an established IS-IS adjacency. This may result in traffic disruption and loss of IP reachability for prefixes advertised through that adjacency."}], "lastModified": "2026-09-16T00:17:05.000", "sourceIdentifier": "psirt@arista.com"}