{"id":"CVE-2026-120978","kind":"vulnerability","aliases":["CVE-2026-120978"],"related":[],"title":"Arista EOS: crafted BGP-LS message restarts the BGP agent unexpectedly","description":"On affected Arista EOS platforms running Border Gateway Protocol with Link State ( BGP-LS) and configured with the Dynamic Path Selection (DPS) consumer role, an attacker who has established an authenticated BGP-LS session with the device can send a crafted message to cause the BGP agent to restart unexpectedly. An Arista Pathfinder deployment is not required.","summary":"On Arista EOS devices running BGP-LS with the Dynamic Path Selection consumer role, a crafted message can make the BGP agent restart unexpectedly. The attacker must already hold an authenticated BGP-LS session with the device, and no Arista Pathfinder deployment is needed.","severity":"medium","cvss":6.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["arista-eos","bgp-ls","infrastructure","network"],"not_affected_if":["no-bgp-ls","no-dps-consumer-role","unauthenticated-only"],"how_to_check":"- Check whether BGP-LS is configured and whether the Dynamic Path Selection consumer role is enabled on the device.\n- Confirm the running EOS version against the affected versions listed by Arista; the sources do not give version ranges.","fix":null,"status":"open","published_at":"2026-11-10T20:18:52+00:00","first_seen_at":"2026-11-10T20:46:03+00:00","triaged_at":"2026-11-10T20:48:08+00:00","updated_at":"2026-11-10T20:48:08+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-11-10T20:48:08Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Arista EOS: crafted BGP-LS message restarts the BGP agent unexpectedly","impact":"low","summary":"On Arista EOS devices running BGP-LS with the Dynamic Path Selection consumer role, a crafted message can make the BGP agent restart unexpectedly. The attacker must already hold an authenticated BGP-LS session with the device, and no Arista Pathfinder deployment is needed.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["arista-eos","bgp-ls","network"],"confidence":0.6,"fix_status":"unknown","needs_auth":"yes","worst_case":"BGP agent restarts unexpectedly, disrupting routing on the device","analyst_note":"Find the Arista security advisory for CVE-2026-120978 to confirm affected EOS versions and the fixed release; the NVD entry alone does not give them.","how_to_check":"- Check whether BGP-LS is configured and whether the Dynamic Path Selection consumer role is enabled on the device.\n- Confirm the running EOS version against the affected versions listed by Arista; the sources do not give version ranges.","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-bgp-ls","no-dps-consumer-role","unauthenticated-only"],"who_is_affected":"Only Arista EOS devices that run BGP-LS and have the Dynamic Path Selection consumer role configured are in scope. An attacker must already have an authenticated BGP-LS session with the device, so devices without BGP-LS or without that role are not affected. Teams running Arista switches or routers with this configuration should look at it; the sources do not state other exposure.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000774,"input_tokens":4584,"output_tokens":631,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-120978':15A,18A '-2026':14A,17A 'affect':74C 'agent':11A,49B,121C 'alreadi':55B 'arista':1A,20B,28B,68B,75C,126C 'arista-eo':19B 'attack':53B,99C 'authent':58B,104C 'bgp':5A,10A,23B,33B,48B,60B,86C,106C,120C 'bgp-ls':4A,22B,32B,59B,85C,105C 'border':79C 'caus':118C 'configur':89C 'consum':40B,96C 'craft':3A,43B,115C 'cve':13A,16A 'deploy':70B,128C 'devic':30B,65B,111C 'dps':95C 'dynam':37B,92C 'eo':2A,21B,29B,76C 'establish':102C 'gateway':80C 'hold':56B 'infrastructur':25B 'link':83C 'ls':6A,24B,34B,61B,87C,107C 'make':46B 'messag':7A,44B,116C 'must':54B 'need':72B 'network':26B 'path':38B,93C 'pathfind':69B,127C 'platform':77C 'protocol':81C 'requir':131C 'restart':8A,50B,123C 'role':41B,97C 'run':31B,78C 'select':39B,94C 'send':113C 'session':62B,108C 'state':84C 'unexpect':12A,51B,124C","nicknames":[],"mitigations":[],"who_affected":"Only Arista EOS devices that run BGP-LS and have the Dynamic Path Selection consumer role configured are in scope. An attacker must already have an authenticated BGP-LS session with the device, so devices without BGP-LS or without that role are not affected. Teams running Arista switches or routers with this configuration should look at it; the sources do not state other exposure.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["aristaeos","bgpls","infrastructure","medium","network"],"campaign_type":null,"search_a":"'-120978':15A,18A '-2026':14A,17A 'agent':11A 'arista':1A 'bgp':5A,10A 'bgp-ls':4A 'craft':3A 'cve':13A,16A 'eo':2A 'ls':6A 'messag':7A 'restart':8A 'unexpect':12A","search_b":"'agent':49B 'alreadi':55B 'arista':20B,28B,68B 'arista-eo':19B 'attack':53B 'authent':58B 'bgp':23B,33B,48B,60B 'bgp-ls':22B,32B,59B 'consum':40B 'craft':43B 'deploy':70B 'devic':30B,65B 'dynam':37B 'eo':21B,29B 'hold':56B 'infrastructur':25B 'ls':24B,34B,61B 'make':46B 'messag':44B 'must':54B 'need':72B 'network':26B 'path':38B 'pathfind':69B 'restart':50B 'role':41B 'run':31B 'select':39B 'session':62B 'unexpect':51B","search_c":"'affect':74C 'agent':121C 'arista':75C,126C 'attack':99C 'authent':104C 'bgp':86C,106C,120C 'bgp-ls':85C,105C 'border':79C 'caus':118C 'configur':89C 'consum':96C 'craft':115C 'deploy':128C 'devic':111C 'dps':95C 'dynam':92C 'eo':76C 'establish':102C 'gateway':80C 'link':83C 'ls':87C,107C 'messag':116C 'path':93C 'pathfind':127C 'platform':77C 'protocol':81C 'requir':131C 'restart':123C 'role':97C 'run':78C 'select':94C 'send':113C 'session':108C 'state':84C 'unexpect':124C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T20:18:52+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/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-2026-120978","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-120978","severity":null,"published_at":"2026-11-10T20:18:52+00:00","modified_at":"2026-11-10T20:18:52+00:00","first_seen_at":"2026-11-10T20:46:03+00:00","fetched_at":"2026-11-10T20:46:03+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"}