{"id":"CVE-2026-121369","kind":"vulnerability","aliases":["CVE-2026-121369"],"related":[],"title":"Arista EOS: link-layer traffic can exhaust CPU and memory, forcing a reboot","description":"On affected platforms running Arista EOS under specific link configurations an attacker with direct connectivity to the system may cause system CPU and memory utilization to increase considerably leading to slow responsiveness and eventually may cause the system to reboot.","summary":"On Arista EOS switches under specific link configurations, an attacker with direct connectivity can drive CPU and memory use up sharply. The device becomes slow and may eventually reboot.","severity":"medium","cvss":6.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["arista-eos","infrastructure","network-gear"],"not_affected_if":["default-config","no-untrusted-direct-connectivity"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T20:18:56+00:00","first_seen_at":"2026-11-10T20:46:04+00:00","triaged_at":"2026-11-10T20:48:03+00:00","updated_at":"2026-11-10T20:48:03+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-10T20:48:03Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Arista EOS: link-layer traffic can exhaust CPU and memory, forcing a reboot","impact":"medium","summary":"On Arista EOS switches under specific link configurations, an attacker with direct connectivity can drive CPU and memory use up sharply. The device becomes slow and may eventually reboot.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["arista-eos","network-gear"],"confidence":0.5,"fix_status":"unknown","needs_auth":"no","worst_case":"switch reboots; service disruption from resource exhaustion","analyst_note":"Find the Arista security advisory for CVE-2026-121369 to get affected EOS versions, the link configurations, and the fixed releases.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-untrusted-direct-connectivity","default-config"],"who_is_affected":"Affected Arista EOS devices with the specific link configurations described in the advisory are exposed to an attacker on a directly connected segment. Network teams should look at Arista switches on segments where untrusted hosts can reach them directly. Devices without those link configurations, or with no reachable untrusted segment, are unlikely to be affected. The sources do not give the exact configurations or affected versions.","user_interaction":"no","product_ecosystem":"vendor","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000713,"input_tokens":4526,"output_tokens":520,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-121369':17A,20A '-2026':16A,19A 'affect':58C 'arista':1A,22B,29B,61C 'arista-eo':21B 'attack':37B,68C 'becom':51B 'caus':76C,92C 'configur':35B,66C 'connect':40B,71C 'consider':84C 'cpu':9A,43B,78C 'cve':15A,18A 'devic':50B 'direct':39B,70C 'drive':42B 'eo':2A,23B,30B,62C 'eventu':55B,90C 'exhaust':8A 'forc':12A 'gear':27B 'increas':83C 'infrastructur':24B 'layer':5A 'lead':85C 'link':4A,34B,65C 'link-lay':3A 'may':54B,75C,91C 'memori':11A,45B,80C 'network':26B 'network-gear':25B 'platform':59C 'reboot':14A,56B,96C 'respons':88C 'run':60C 'sharpli':48B 'slow':52B,87C 'specif':33B,64C 'switch':31B 'system':74C,77C,94C 'traffic':6A 'use':46B 'util':81C","nicknames":[],"mitigations":[],"who_affected":"Affected Arista EOS devices with the specific link configurations described in the advisory are exposed to an attacker on a directly connected segment. Network teams should look at Arista switches on segments where untrusted hosts can reach them directly. Devices without those link configurations, or with no reachable untrusted segment, are unlikely to be affected. The sources do not give the exact configurations or affected versions.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["aristaeos","infrastructure","medium","networkgear"],"campaign_type":null,"search_a":"'-121369':17A,20A '-2026':16A,19A 'arista':1A 'cpu':9A 'cve':15A,18A 'eo':2A 'exhaust':8A 'forc':12A 'layer':5A 'link':4A 'link-lay':3A 'memori':11A 'reboot':14A 'traffic':6A","search_b":"'arista':22B,29B 'arista-eo':21B 'attack':37B 'becom':51B 'configur':35B 'connect':40B 'cpu':43B 'devic':50B 'direct':39B 'drive':42B 'eo':23B,30B 'eventu':55B 'gear':27B 'infrastructur':24B 'link':34B 'may':54B 'memori':45B 'network':26B 'network-gear':25B 'reboot':56B 'sharpli':48B 'slow':52B 'specif':33B 'switch':31B 'use':46B","search_c":"'affect':58C 'arista':61C 'attack':68C 'caus':76C,92C 'configur':66C 'connect':71C 'consider':84C 'cpu':78C 'direct':70C 'eo':62C 'eventu':90C 'increas':83C 'lead':85C 'link':65C 'may':75C,91C 'memori':80C 'platform':59C 'reboot':96C 'respons':88C 'run':60C 'slow':87C 'specif':64C 'system':74C,77C,94C 'util':81C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T20:18:56+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:P/AC:L/AT:N/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","cvss_by":"psirt@arista.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-121369","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121369","severity":null,"published_at":"2026-11-10T20:18:56+00:00","modified_at":"2026-11-10T20:18:56+00:00","first_seen_at":"2026-11-10T20:46:04+00:00","fetched_at":"2026-11-10T20:46:04+00:00","note":null}],"documents":[],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}