On affected platforms running Arista EOS with IS-IS configured, an unauthenticated attacker who can inject a specially crafted IS-IS LSP PDU can cause the legitimate LSP to be unexpectedly purged from the IS-IS link-state database. This may result in traffic loss.
"}]}],"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":"In order to be vulnerable to CVE-2026-73459, the following condition must be met: \n\nIS-IS should be configured.\n\n\n\nswitch# show isis summary\nIS-IS Instance: 1 VRF: default\n Instance ID: 0\n System ID: 1111.1111.1001, administratively enabled\n Router ID: IPv4: 0.0.0.0\n Multi Topology disabled, not attached\n IPv4 Preference: Level 1: 115, Level 2: 115\n IPv6 Preference: Level 1: 115, Level 2: 115\n IS-Type: Level 1 and 2, Number active interfaces: 1\n Routes both IPv4 and IPv6\n LSP size maximum: Level 1: 1492, Level 2: 1492\n Interval Type Max Wait Initial Wait Hold Interval\n ----------------------- -------- ------------ -------------\n LSP generation interval 5 s 50 ms 50 ms\n SPF interval 30000 ms 300 ms 80 ms\n Current SPF hold interval(ms): Level 1: 80, Level 2: 80\n Last Level 1 SPF run 9 seconds ago\n Last Level 2 SPF run 9 seconds ago\n CSNP generation interval: 10 seconds\n Dynamic Flooding: Disabled\n Authentication mode: Level 1: None, Level 2: None\n Graceful Restart: Disabled, Graceful Restart Helper: Enabled\n Area addresses: 40\n level 1: number DIS interfaces: 0, LSDB size: 1\n Area Leader: None\n Overload Bit is not set. \n level 2: number DIS interfaces: 0, LSDB size: 1\n Area Leader: None\n Overload Bit is not set. \n Redistributed Level 1 routes: 0 limit: Not Configured\n Redistributed Level 2 routes: 0 limit: Not Configured\n\n\n\nIf IS-IS is not configured, there is no exposure to this issue.\n\n\n\n\nswitch#show isis summary\nswitch#","supportingMedia":[{"type":"text/html","base64":false,"value":"In order to be vulnerable to CVE-2026-73459, the following condition must be met:
IS-IS should be configured.
switch# show isis summary\nIS-IS Instance: 1 VRF: default\n Instance ID: 0\n System ID: 1111.1111.1001, administratively enabled\n Router ID: IPv4: 0.0.0.0\n Multi Topology disabled, not attached\n IPv4 Preference: Level 1: 115, Level 2: 115\n IPv6 Preference: Level 1: 115, Level 2: 115\n IS-Type: Level 1 and 2, Number active interfaces: 1\n Routes both IPv4 and IPv6\n LSP size maximum: Level 1: 1492, Level 2: 1492\n Interval Type Max Wait Initial Wait Hold Interval\n ----------------------- -------- ------------ -------------\n LSP generation interval 5 s 50 ms 50 ms\n SPF interval 30000 ms 300 ms 80 ms\n Current SPF hold interval(ms): Level 1: 80, Level 2: 80\n Last Level 1 SPF run 9 seconds ago\n Last Level 2 SPF run 9 seconds ago\n CSNP generation interval: 10 seconds\n Dynamic Flooding: Disabled\n Authentication mode: Level 1: None, Level 2: None\n Graceful Restart: Disabled, Graceful Restart Helper: Enabled\n Area addresses: 40\n level 1: number DIS interfaces: 0, LSDB size: 1\n Area Leader: None\n Overload Bit is not set. \n level 2: number DIS interfaces: 0, LSDB size: 1\n Area Leader: None\n Overload Bit is not set. \n Redistributed Level 1 routes: 0 limit: Not Configured\n Redistributed Level 2 routes: 0 limit: Not Configured
If IS-IS is not configured, there is no exposure to this issue.
switch#show isis summary\nswitch#"}]}],"workarounds":[{"lang":"en","value":"No workaround is available for this issue.","supportingMedia":[{"type":"text/html","base64":false,"value":"
No workaround is available for this issue.
"}]}],"solutions":[{"lang":"en","value":"The recommended resolution is to upgrade to a fixed software version.","supportingMedia":[{"type":"text/html","base64":false,"value":"The recommended resolution is to upgrade to a fixed software version.
"}]}],"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":["BUG1840507"]},"x_generator":{"engine":"Vulnogram 1.0.5"}}}}