CVE-2026-73446

{"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": "2026-09-16T19:34:18.384Z"}, "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\u00a0\u00a0\u00a0net 49.0001.1111.1111.1001.00\nswitch(config-if-Et1)#show active\ninterface Ethernet1\n\u00a0\u00a0\u00a0isis enable 1\n\n\n\nswitch#show isis interface detail\nIS-IS Instance: 1 VRF: default\n\n\n\u00a0\u00a0Interface Ethernet1:\n\u00a0\u00a0\u00a0\u00a0Index: 4 SNPA: 2:2:0:1:0:0\n\u00a0\u00a0\u00a0\u00a0MTU: 1497 Type: broadcast\n\u00a0\u00a0\u00a0\u00a0Supported address families: IPv4, IPv6\n\u00a0\u00a0\u00a0\u00a0Area proxy boundary is disabled\n\u00a0\u00a0\u00a0\u00a0BFD IPv4 is disabled\n\u00a0\u00a0\u00a0\u00a0BFD IPv6 is disabled\n\u00a0\u00a0\u00a0\u00a0Hello padding is enabled\n\u00a0\u00a0\u00a0\u00a0Level 1:\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Metric: 10, Number of adjacencies: 1\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0LAN-ID: 1111.1111.1001.04, Priority: 64\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0DIS: 1111.1111.1001, DIS priority: 64\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Authentication mode: None\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0TI-LFA protection is disabled for IPv4\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0TI-LFA protection is disabled for IPv6\n\u00a0\u00a0\u00a0\u00a0Adjacency 1111.1111.1002:\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0State: UP, Level: 1 Type: Level 1 IS\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Advertised hold time: 9\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Neighbor supported address families: IPv4, IPv6\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Address family match: Enabled\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0SNPA: 2:2:0:2:0:0, Priority: 64\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0IPv4 interface address: 10.0.0.2\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0IPv6 interface address: fe80::2:ff:fe02:0\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Area 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\u00a0\u00a0Interface Ethernet1:\n\u00a0\u00a0\u00a0\u00a0Index: 4 SNPA: P2P\n\u00a0\u00a0\u00a0\u00a0MTU: 1497 Type: point-to-point\n\u00a0\u00a0\u00a0\u00a0Supported address families: IPv4, IPv6\n\u00a0\u00a0\u00a0\u00a0Area proxy boundary is disabled\n\u00a0\u00a0\u00a0\u00a0BFD IPv4 is disabled\n\u00a0\u00a0\u00a0\u00a0BFD IPv6 is disabled\n\u00a0\u00a0\u00a0\u00a0Hello padding is enabled\n\u00a0\u00a0\u00a0\u00a0Local fast flooding is disabled\n\u00a0\u00a0\u00a0\u00a0Level 1:\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Metric: 10, Number of adjacencies: 1\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Link-ID: 04\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Authentication mode: None\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0TI-LFA protection is disabled for IPv4\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0TI-LFA protection is disabled for IPv6\n\u00a0\u00a0\u00a0\u00a0Adjacency 1111.1111.1002:\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0State: UP, Level: 1 Type: Level 1 IS\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Advertised hold time: 30\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Neighbor supported address families: IPv4, IPv6\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Address family match: Enabled\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0IPv4 interface address: 1.0.0.2\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0IPv6 interface address: fe80::2:ff:fe02:0\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Area addresses: 49.0001\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Peer 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"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-09-16T19:34:09.117613Z", "id": "CVE-2026-73446", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-09-16T19:34:18.384Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-73446", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-09-16T19:34:09.117613Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-09-16T19:34:14.791Z"}}], "cna": {"title": "Security Advisory 0160", "source": {"defects": ["BUG1840504"], "advisory": "0160", "discovery": "UNKNOWN"}, "credits": [{"lang": "en", "type": "finder", "value": "This issue was discovered internally by Arista and the company is not aware of any malicious uses of these issues in customer networks."}], "impacts": [{"capecId": "CAPEC-272", "descriptions": [{"lang": "en", "value": "CAPEC-272 Protocol Manipulation"}]}], "metrics": [{"format": "CVSS", "cvssV3_1": {"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"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}, {"format": "CVSS", "cvssV4_0": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 7, "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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subAvailabilityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"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"}], "solutions": [{"lang": "en", "value": "The recommended resolution is to upgrade to a fixed software version.", "supportingMedia": [{"type": "text/html", "value": "<p>The recommended resolution is to upgrade to a fixed software version.</p>", "base64": false}]}], "references": [{"url": "https://www.arista.com/en/support/advisories-notices/security-advisory/24716-security-advisory-0160", "name": "Security Advisory 0160", "tags": ["vendor-advisory"]}], "workarounds": [{"lang": "en", "value": "No workaround is available for this issue.", "supportingMedia": [{"type": "text/html", "value": "<p>No workaround is available for this issue.</p>", "base64": false}]}], "x_generator": {"engine": "Vulnogram 1.0.5"}, "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", "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>", "base64": false}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-696", "description": "CWE-696: Incorrect Behavior Order"}]}], "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\u00a0\u00a0\u00a0net 49.0001.1111.1111.1001.00\nswitch(config-if-Et1)#show active\ninterface Ethernet1\n\u00a0\u00a0\u00a0isis enable 1\n\n\n\nswitch#show isis interface detail\nIS-IS Instance: 1 VRF: default\n\n\n\u00a0\u00a0Interface Ethernet1:\n\u00a0\u00a0\u00a0\u00a0Index: 4 SNPA: 2:2:0:1:0:0\n\u00a0\u00a0\u00a0\u00a0MTU: 1497 Type: broadcast\n\u00a0\u00a0\u00a0\u00a0Supported address families: IPv4, IPv6\n\u00a0\u00a0\u00a0\u00a0Area proxy boundary is disabled\n\u00a0\u00a0\u00a0\u00a0BFD IPv4 is disabled\n\u00a0\u00a0\u00a0\u00a0BFD IPv6 is disabled\n\u00a0\u00a0\u00a0\u00a0Hello padding is enabled\n\u00a0\u00a0\u00a0\u00a0Level 1:\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Metric: 10, Number of adjacencies: 1\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0LAN-ID: 1111.1111.1001.04, Priority: 64\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0DIS: 1111.1111.1001, DIS priority: 64\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Authentication mode: None\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0TI-LFA protection is disabled for IPv4\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0TI-LFA protection is disabled for IPv6\n\u00a0\u00a0\u00a0\u00a0Adjacency 1111.1111.1002:\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0State: UP, Level: 1 Type: Level 1 IS\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Advertised hold time: 9\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Neighbor supported address families: IPv4, IPv6\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Address family match: Enabled\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0SNPA: 2:2:0:2:0:0, Priority: 64\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0IPv4 interface address: 10.0.0.2\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0IPv6 interface address: fe80::2:ff:fe02:0\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Area 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\u00a0\u00a0Interface Ethernet1:\n\u00a0\u00a0\u00a0\u00a0Index: 4 SNPA: P2P\n\u00a0\u00a0\u00a0\u00a0MTU: 1497 Type: point-to-point\n\u00a0\u00a0\u00a0\u00a0Supported address families: IPv4, IPv6\n\u00a0\u00a0\u00a0\u00a0Area proxy boundary is disabled\n\u00a0\u00a0\u00a0\u00a0BFD IPv4 is disabled\n\u00a0\u00a0\u00a0\u00a0BFD IPv6 is disabled\n\u00a0\u00a0\u00a0\u00a0Hello padding is enabled\n\u00a0\u00a0\u00a0\u00a0Local fast flooding is disabled\n\u00a0\u00a0\u00a0\u00a0Level 1:\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Metric: 10, Number of adjacencies: 1\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Link-ID: 04\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Authentication mode: None\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0TI-LFA protection is disabled for IPv4\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0TI-LFA protection is disabled for IPv6\n\u00a0\u00a0\u00a0\u00a0Adjacency 1111.1111.1002:\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0State: UP, Level: 1 Type: Level 1 IS\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Advertised hold time: 30\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Neighbor supported address families: IPv4, IPv6\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Address family match: Enabled\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0IPv4 interface address: 1.0.0.2\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0IPv6 interface address: fe80::2:ff:fe02:0\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Area addresses: 49.0001\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Peer fast flooding is disabled", "supportingMedia": [{"type": "text/html", "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>", "base64": false}]}], "providerMetadata": {"orgId": "c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7", "shortName": "Arista", "dateUpdated": "2026-09-15T23:08:19.771Z"}}}, "cveMetadata": {"cveId": "CVE-2026-73446", "state": "PUBLISHED", "dateUpdated": "2026-09-16T19:34:18.384Z", "dateReserved": "2026-08-12T16:42:47.920Z", "assignerOrgId": "c8b34d1a-69ae-45c3-88fe-f3b3d44f39b7", "datePublished": "2026-09-15T23:08:19.771Z", "assignerShortName": "Arista"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "EOS", "vendor": "Arista Networks", "versions": [{"lessThanOrEqual": "4.36.1F", "status": "affected", "version": "4.36.0", "versionType": "custom"}, {"lessThanOrEqual": "4.35.5M", "status": "affected", "version": "4.35.0", "versionType": "custom"}, {"lessThanOrEqual": "4.34.7.1M", "status": "affected", "version": "4.34.0", "versionType": "custom"}, {"lessThanOrEqual": "4.33.9M", "status": "affected", "version": "4.33.0", "versionType": "custom"}, {"lessThan": "4.33.0F", "status": "affected", "version": "4.32.0", "versionType": "custom"}, {"lessThan": "4.32.0F", "status": "affected", "version": "4.31.0", "versionType": "custom"}]}], "source": "psirt@arista.com"}], "cveTags": [], "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."}], "id": "CVE-2026-73446", "lastModified": "2026-09-16T20:17:26.997", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 4.0, "source": "psirt@arista.com", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "ADJACENT", "availabilityRequirement": "NOT_DEFINED", "baseScore": 7.0, "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": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "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", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "psirt@arista.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-73446", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-09-16T19:34:09.117613Z", "version": "2.0.3"}}]}, "published": "2026-09-16T00:17:05.000", "references": [{"source": "psirt@arista.com", "url": "https://www.arista.com/en/support/advisories-notices/security-advisory/24716-security-advisory-0160"}], "sourceIdentifier": "psirt@arista.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-696"}], "source": "psirt@arista.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[4.36.0,4.36.1F]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[4.35.0,4.35.5M]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[4.34.0,4.34.7.1M]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[4.33.0,4.33.9M]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[4.32.0,4.33.0F)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[4.31.0,4.32.0F)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "original": {"product": "EOS", "source": "cna", "vendor": "Arista Networks"}, "product": "eos", "vendor": "arista"}], "created": "2026-09-16T18:15:15.025393+00:00", "title": "Unauthenticated IS\u2011IS Hello Packet Causes Adjacency Tear and Traffic Disruption in Arista EOS", "updated": "2026-09-29T13:22:48.403795+00:00", "vendors": ["arista", "arista$PRODUCT$eos"]}