{"id":"CVE-2026-121291","kind":"vulnerability","aliases":["CVE-2026-121291"],"related":[],"title":"Arista EOS: crafted RPKI Error Report stalls ROA publication and BGP origin validation","description":"A crafted Error Report can leave EOS stuck believing that a cache reset is in progress, preventing ROA publication, withdrawal reconciliation, and BGP origin-validation updates.","summary":"A crafted Error Report can leave EOS stuck believing a cache reset is in progress. While stuck, ROA publication, withdrawal reconciliation and BGP origin-validation updates are blocked.","severity":"high","cvss":8.3,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"EOS","fixed":["4.35.7M","4.36.3M"],"affected":">= 4.35.0F, <= 4.35.6M; >= 4.36.0F, <= 4.36.2F; 4.37.0F","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["arista","bgp","eos","infrastructure","network-devices","routing","rpki"],"not_affected_if":["no-rpki-configured"],"how_to_check":"On the switch run 'show bgp rpki cache': exposed only if EOS is 4.37.0F, 4.36.0F-4.36.2F or 4.35.0F-4.35.6M AND an RPKI cache is configured under router bgp with an RPKI-RTR session established. Signs it happened: 'grep \"RPKI-4-CACHE_ERROR: Received\" /var/log/eos' (Internal Error / No Data Available), 'show bgp rpki cache cache1 counters errors', and a 'Last full sync' time in 'show bgp rpki cache cache1' that no longer advances.","fix":"Upgrade to EOS 4.36.3M or later (4.36 train) or 4.35.7M or later (4.35 train). No fixed release is named for 4.37.0F in the advisory; check Arista.","status":"open","published_at":"2026-11-10T20:18:54+00:00","first_seen_at":"2026-11-10T20:46:03+00:00","triaged_at":"2026-11-10T20:47:29+00:00","updated_at":"2026-11-10T20:56:28+00:00","category":"infrastructure","confidence":0.85,"triage":{"at":"2026-11-10T20:47:29Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"EOS: crafted Error Report stalls ROA publication and BGP origin validation","impact":"medium","summary":"A crafted Error Report can leave EOS stuck believing a cache reset is in progress. While stuck, ROA publication, withdrawal reconciliation and BGP origin-validation updates are blocked.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["bgp","rpki","routing"],"confidence":0.5,"fix_status":"unknown","needs_auth":"unknown","worst_case":"Route origin validation stops updating, so routing decisions go stale","analyst_note":"Confirm which product EOS is (likely an RPKI validator or routing stack), its affected and fixed versions, and any workaround, from the NVD entry.","how_to_check":"unknown","plain_action":"","product_name":"EOS","needs_analyst":true,"not_affected_if":[],"who_is_affected":"unknown","user_interaction":"no","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000648,"input_tokens":4517,"output_tokens":392,"severity_before":"high"},"analyst_status":"done","analyst_note":"Confirm which product EOS is (likely an RPKI validator or routing stack), its affected and fixed versions, and any workaround, from the NVD entry.","search":"'-121291':16A,19A '-2026':15A,18A 'arista':1A,21B 'believ':38B,67C 'bgp':11A,22B,52B,81C 'block':58B 'cach':40B,70C 'craft':3A,31B,60C 'cve':14A,17A 'devic':27B 'eo':2A,23B,36B,65C 'eos':20A 'error':5A,32B,61C 'infrastructur':24B 'leav':35B,64C 'network':26B 'network-devic':25B 'origin':12A,54B,83C 'origin-valid':53B,82C 'prevent':75C 'progress':44B,74C 'public':9A,48B,77C 'reconcili':50B,79C 'report':6A,33B,62C 'reset':41B,71C 'roa':8A,47B,76C 'rout':28B 'rpki':4A,29B 'stall':7A 'stuck':37B,46B,66C 'updat':56B,85C 'valid':13A,55B,84C 'withdraw':49B,78C","nicknames":[],"mitigations":[],"who_affected":"Arista switches and routers running EOS 4.35.0F-4.35.6M, 4.36.0F-4.36.2F or 4.37.0F that use RPKI origin validation with a configured RPKI-RTR cache (including CloudEOS, cEOS-lab, vEOS-lab, CloudVision eXchange). A crafted Error Report from the cache leaves the device believing a cache reset is in progress, blocking ROA updates and origin-validation changes. Skip if you do not use RPKI caches or run EOS before 4.35.0F.","tier":"B","verified":{"fix":{"at":"2026-11-10T20:56:28Z","by":"analyst","doc":"https://www.arista.com/en/support/advisories-notices/security-advisory/25044-security-advisory-0222","run_id":2727},"products":{"at":"2026-11-10T20:56:28Z","by":"analyst","doc":"https://www.arista.com/en/support/advisories-notices/security-advisory/25044-security-advisory-0222","run_id":2727},"how_to_check":{"at":"2026-11-10T20:56:28Z","by":"analyst","doc":"https://www.arista.com/en/support/advisories-notices/security-advisory/25044-security-advisory-0222","run_id":2727},"who_affected":{"at":"2026-11-10T20:56:28Z","by":"analyst","doc":"https://www.arista.com/en/support/advisories-notices/security-advisory/25044-security-advisory-0222","run_id":2727}},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":["eos"],"ptokens":["eos"],"labels":["arista","bgp","eos","high","infrastructure","networkdevices","routing","rpki","vendor"],"campaign_type":null,"search_a":"'-121291':16A,19A '-2026':15A,18A 'arista':1A 'bgp':11A 'craft':3A 'cve':14A,17A 'eo':2A 'eos':20A 'error':5A 'origin':12A 'public':9A 'report':6A 'roa':8A 'rpki':4A 'stall':7A 'valid':13A","search_b":"'arista':21B 'believ':38B 'bgp':22B,52B 'block':58B 'cach':40B 'craft':31B 'devic':27B 'eo':23B,36B 'error':32B 'infrastructur':24B 'leav':35B 'network':26B 'network-devic':25B 'origin':54B 'origin-valid':53B 'progress':44B 'public':48B 'reconcili':50B 'report':33B 'reset':41B 'roa':47B 'rout':28B 'rpki':29B 'stuck':37B,46B 'updat':56B 'valid':55B 'withdraw':49B","search_c":"'believ':67C 'bgp':81C 'cach':70C 'craft':60C 'eo':65C 'error':61C 'leav':64C 'origin':83C 'origin-valid':82C 'prevent':75C 'progress':74C 'public':77C 'reconcili':79C 'report':62C 'reset':71C 'roa':76C 'stuck':66C 'updat':85C 'valid':84C 'withdraw':78C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T20:18:54+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:L/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-2026-121291","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121291","severity":null,"published_at":"2026-11-10T20:18:54+00:00","modified_at":"2026-11-10T20:18:54+00:00","first_seen_at":"2026-11-10T20:46:03+00:00","fetched_at":"2026-11-10T20:46:03+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-121291:2727","url":"https://www.arista.com/en/support/advisories-notices/security-advisory/25044-security-advisory-0222","severity":null,"published_at":"2026-11-10T20:56:28+00:00","modified_at":"2026-11-10T20:56:28+00:00","first_seen_at":"2026-11-10T20:56:28+00:00","fetched_at":"2026-11-10T20:56:28+00:00","note":"Arista SA 0222 (read via fetch tool, summarised); NVD lists same versions. Search/X not used. 4.37.0F affected, no fixed 4.37 release stated.","cites":["https://www.arista.com/en/support/advisories-notices/security-advisory/25044-security-advisory-0222"]}],"documents":[{"id":118336,"url":"https://www.arista.com/en/support/advisories-notices/security-advisory/25044-security-advisory-0222","title":"Arista Security Advisory 0222","kind":"advisory","source":"analyst","publisher":null,"text":null,"published_at":null,"relation":"advisory","confidence":null,"note":null}],"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"}