{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-73446","assignerOrgId":"c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7","state":"PUBLISHED","assignerShortName":"Arista","dateReserved":"2026-08-12T16:42:47.920Z","datePublished":"2026-09-15T23:08:19.771Z","dateUpdated":"2026-09-15T23:08:19.771Z"},"containers":{"cna":{"providerMetadata":{"orgId":"c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7","shortName":"Arista","dateUpdated":"2026-09-15T23:08:19.771Z"},"title":"Security Advisory 0160","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-696","description":"CWE-696: Incorrect Behavior Order","type":"CWE"}]}],"impacts":[{"capecId":"CAPEC-272","descriptions":[{"lang":"en","value":"CAPEC-272 Protocol Manipulation"}]}],"affected":[{"vendor":"Arista Networks","product":"EOS","versions":[{"status":"affected","version":"4.36.0","lessThanOrEqual":"4.36.1F","versionType":"custom"},{"status":"affected","version":"4.35.0","lessThanOrEqual":"4.35.5M","versionType":"custom"},{"status":"affected","version":"4.34.0","lessThanOrEqual":"4.34.7.1M","versionType":"custom"},{"status":"affected","version":"4.33.0","lessThanOrEqual":"4.33.9M","versionType":"custom"},{"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"}],"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.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>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.</p>"}]}],"references":[{"url":"https://www.arista.com/en/support/advisories-notices/security-advisory/24716-security-advisory-0160","name":"Security Advisory 0160","tags":["vendor-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","baseSeverity":"HIGH","baseScore":7.4,"vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"ADJACENT","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"HIGH","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,"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"}}],"configurations":[{"lang":"en","value":"IS-IS must be enabled on a broadcast (LAN) interface AND there should be an active IS-IS adjacency on that interface:\n\n\n\nswitch(config-router-isis)#show active\nrouter isis 1\n   net 49.0001.1111.1111.1001.00\nswitch(config-if-Et1)#show active\ninterface Ethernet1\n   isis enable 1\n\n\n\nswitch#show isis interface detail\nIS-IS Instance: 1 VRF: default\n\n\n  Interface Ethernet1:\n    Index: 4 SNPA: 2:2:0:1:0:0\n    MTU: 1497 Type: broadcast\n    Supported address families: IPv4, IPv6\n    Area proxy boundary is disabled\n    BFD IPv4 is disabled\n    BFD IPv6 is disabled\n    Hello padding is enabled\n    Level 1:\n      Metric: 10, Number of adjacencies: 1\n      LAN-ID: 1111.1111.1001.04, Priority: 64\n      DIS: 1111.1111.1001, DIS priority: 64\n      Authentication mode: None\n      TI-LFA protection is disabled for IPv4\n      TI-LFA protection is disabled for IPv6\n    Adjacency 1111.1111.1002:\n      State: UP, Level: 1 Type: Level 1 IS\n      Advertised hold time: 9\n      Neighbor supported address families: IPv4, IPv6\n      Address family match: Enabled\n      SNPA: 2:2:0:2:0:0, Priority: 64\n      IPv4 interface address: 10.0.0.2\n      IPv6 interface address: fe80::2:ff:fe02:0\n      Area addresses: 49.0001\n\n\n\n\n\nIf IS-IS is not configured OR IS-IS is configured only on point-to-point interfaces, there is no exposure to this issue.\n\n\n\n\n\nswitch#show isis interface detail\nIS-IS Instance: 1 VRF: default\n \n  Interface Ethernet1:\n    Index: 4 SNPA: P2P\n    MTU: 1497 Type: point-to-point\n    Supported address families: IPv4, IPv6\n    Area proxy boundary is disabled\n    BFD IPv4 is disabled\n    BFD IPv6 is disabled\n    Hello padding is enabled\n    Local fast flooding is disabled\n    Level 1:\n      Metric: 10, Number of adjacencies: 1\n      Link-ID: 04\n      Authentication mode: None\n      TI-LFA protection is disabled for IPv4\n      TI-LFA protection is disabled for IPv6\n    Adjacency 1111.1111.1002:\n      State: UP, Level: 1 Type: Level 1 IS\n      Advertised hold time: 30\n      Neighbor supported address families: IPv4, IPv6\n      Address family match: Enabled\n      IPv4 interface address: 1.0.0.2\n      IPv6 interface address: fe80::2:ff:fe02:0\n      Area addresses: 49.0001\n      Peer fast flooding is disabled","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>IS-IS must be enabled on a broadcast (LAN) interface AND there should be an active IS-IS adjacency on that interface:</p><pre>switch(config-router-isis)#show active\nrouter isis 1\n&nbsp;&nbsp;&nbsp;net 49.0001.1111.1111.1001.00\nswitch(config-if-Et1)#show active\ninterface Ethernet1\n&nbsp;&nbsp;&nbsp;isis enable 1<br><br><pre>switch#show isis interface detail\nIS-IS Instance: 1 VRF: default\n<br>\n&nbsp;&nbsp;Interface Ethernet1:\n&nbsp;&nbsp;&nbsp;&nbsp;Index: 4 SNPA: 2:2:0:1:0:0\n&nbsp;&nbsp;&nbsp;&nbsp;MTU: 1497 Type: broadcast\n&nbsp;&nbsp;&nbsp;&nbsp;Supported address families: IPv4, IPv6\n&nbsp;&nbsp;&nbsp;&nbsp;Area proxy boundary is disabled\n&nbsp;&nbsp;&nbsp;&nbsp;BFD IPv4 is disabled\n&nbsp;&nbsp;&nbsp;&nbsp;BFD IPv6 is disabled\n&nbsp;&nbsp;&nbsp;&nbsp;Hello padding is enabled\n&nbsp;&nbsp;&nbsp;&nbsp;Level 1:\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Metric: 10, Number of adjacencies: 1\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;LAN-ID: 1111.1111.1001.04, Priority: 64\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;DIS: 1111.1111.1001, DIS priority: 64\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Authentication mode: None\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TI-LFA protection is disabled for IPv4\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TI-LFA protection is disabled for IPv6\n&nbsp;&nbsp;&nbsp;&nbsp;Adjacency 1111.1111.1002:\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;State: UP, Level: 1 Type: Level 1 IS\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Advertised hold time: 9\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Neighbor supported address families: IPv4, IPv6\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Address family match: Enabled\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;SNPA: 2:2:0:2:0:0, Priority: 64\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;IPv4 interface address: 10.0.0.2\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;IPv6 interface address: fe80::2:ff:fe02:0\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Area addresses: 49.0001</pre></pre><p>If IS-IS is not configured OR IS-IS is configured only on point-to-point interfaces, there is no exposure to this issue.<br><br></p><pre>switch#show isis interface detail\nIS-IS Instance: 1 VRF: default\n \n&nbsp;&nbsp;Interface Ethernet1:\n&nbsp;&nbsp;&nbsp;&nbsp;Index: 4 SNPA: P2P\n&nbsp;&nbsp;&nbsp;&nbsp;MTU: 1497 Type: point-to-point\n&nbsp;&nbsp;&nbsp;&nbsp;Supported address families: IPv4, IPv6\n&nbsp;&nbsp;&nbsp;&nbsp;Area proxy boundary is disabled\n&nbsp;&nbsp;&nbsp;&nbsp;BFD IPv4 is disabled\n&nbsp;&nbsp;&nbsp;&nbsp;BFD IPv6 is disabled\n&nbsp;&nbsp;&nbsp;&nbsp;Hello padding is enabled\n&nbsp;&nbsp;&nbsp;&nbsp;Local fast flooding is disabled\n&nbsp;&nbsp;&nbsp;&nbsp;Level 1:\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Metric: 10, Number of adjacencies: 1\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Link-ID: 04\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Authentication mode: None\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TI-LFA protection is disabled for IPv4\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TI-LFA protection is disabled for IPv6\n&nbsp;&nbsp;&nbsp;&nbsp;Adjacency 1111.1111.1002:\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;State: UP, Level: 1 Type: Level 1 IS\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Advertised hold time: 30\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Neighbor supported address families: IPv4, IPv6\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Address family match: Enabled\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;IPv4 interface address: 1.0.0.2\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;IPv6 interface address: fe80::2:ff:fe02:0\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Area addresses: 49.0001\n&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Peer fast flooding is disabled<br></pre>"}]}],"workarounds":[{"lang":"en","value":"No workaround is available for this issue.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>No workaround is available for this issue.</p>"}]}],"solutions":[{"lang":"en","value":"The recommended resolution is to upgrade to a fixed software version.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>The recommended resolution is to upgrade to a fixed software version.</p>"}]}],"credits":[{"lang":"en","value":"This issue was discovered internally by Arista and the company is not aware of any malicious uses of these issues in customer networks.","type":"finder"}],"source":{"advisory":"0160","discovery":"UNKNOWN","defects":["BUG1840504"]},"x_generator":{"engine":"Vulnogram 1.0.5"}}}}