{"id":"CVE-2020-3569","kind":"vulnerability","aliases":["CVE-2020-3569"],"related":[],"title":"Cisco IOS XR: Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability","description":"Multiple vulnerabilities in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to either immediately crash the Internet Group Management Protocol (IGMP) process or make it consume available memory and eventually crash. The memory consumption may negatively impact other processes that are running on the device. These vulnerabilities are due to the incorrect handling of IGMP packets. An attacker could exploit these vulnerabilities by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to immediately crash the IGMP process or cause memory exhaustion, resulting in other processes becoming unstable. These processes may include, but are not limited to, interior and exterior routing protocols. Cisco will release software updates that address these vulnerabilities.","summary":"Cisco IOS XR routers mishandle IGMP packets when DVMRP is in use, so an unauthenticated remote attacker can crash the IGMP process or exhaust memory until it crashes. CISA lists it as actively exploited.","severity":"high","cvss":8.6,"epss":0.0332,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Cisco IOS XR","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["cisco","exploited","infrastructure","ios-xr","network-operators"],"not_affected_if":["dvmrp-disabled","non-ios-xr"],"how_to_check":null,"fix":"Apply the updates per Cisco's vendor instructions; the specific fixed release is unknown from the sources.","status":"open","published_at":"2020-09-23T01:15:15+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:33:45+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-23T21:33:45Z","model":"claude-haiku-5-5","output":{"fix":"Apply the updates per Cisco's vendor instructions; the specific fixed release is unknown from the sources.","reach":"network","impact":"medium","summary":"Cisco IOS XR routers mishandle IGMP packets when DVMRP is in use, so an unauthenticated remote attacker can crash the IGMP process or exhaust memory until it crashes. CISA lists it as actively exploited.","category":"infrastructure","who_cares":["cisco","ios-xr","network-operators"],"confidence":0.6,"needs_auth":"no","worst_case":"Routing IGMP process crashes or router memory is exhausted, causing an outage.","analyst_note":"Find the affected IOS XR release range and fixed versions and the DVMRP configuration check in the Cisco advisory for CVE-2020-3569.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["dvmrp-disabled","non-ios-xr"],"user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000472,"input_tokens":2897,"output_tokens":364,"severity_before":"unknown"},"analyst_status":"queued","analyst_note":"Find the affected IOS XR release range and fixed versions and the DVMRP configuration check in the Cisco advisory for CVE-2020-3569.","search":"'-2020':13A,16A '-3569':14A,17A 'activ':62B 'address':189C 'affect':144C 'allow':81C,150C 'attack':46B,85C,132C,152C 'avail':101C 'becom':167C 'caus':160C 'cisa':58B 'cisco':1A,4A,18A,21B,30B,76C,183C 'consum':100C 'consumpt':108C 'could':80C,133C,149C 'craft':139C 'crash':48B,57B,89C,105C,155C 'cve':12A,15A 'devic':119C,145C 'distanc':68C 'due':123C 'dvmrp':8A,38B,73C 'either':87C 'eventu':104C 'exhaust':10A,53B,162C 'exploit':22B,63B,134C,148C 'exterior':180C 'featur':74C 'group':92C 'handl':127C 'igmp':35B,50B,95C,129C,140C,157C 'immedi':88C,154C 'impact':111C 'includ':172C 'incorrect':126C 'infrastructur':23B 'interior':178C 'internet':91C 'io':2A,5A,25B,31B,77C 'ios':19A 'ios-xr':24B 'limit':176C 'list':59B 'make':98C 'manag':93C 'may':109C,171C 'memori':9A,54B,102C,107C,161C 'mishandl':34B 'multicast':70C 'multipl':64C 'negat':110C 'network':28B 'network-oper':27B 'oper':29B 'packet':36B,130C 'process':51B,96C,113C,158C,166C,170C 'protocol':72C,94C,182C 'releas':185C 'remot':45B,84C 'result':163C 'rout':71C,181C 'router':33B 'run':116C 'send':138C 'softwar':7A,79C,186C 'success':147C 'traffic':141C 'unauthent':44B,83C 'unstabl':168C 'updat':187C 'use':41B 'vector':69C 'vulner':11A,65C,121C,136C,191C 'xr':3A,6A,20A,26B,32B,78C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2020-09-23T01:15:15+00:00","kev":{"dateAdded":"2021-11-03","dueDate":"2022-05-03","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","cvss_by":"psirt@cisco.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2020-3569","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-3569","severity":null,"published_at":"2021-11-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:53+00:00","fetched_at":"2026-10-25T11:39:17+00:00","note":null},{"source":"epss","external_id":"CVE-2020-3569","url":"https://api.first.org/data/v1/epss?cve=CVE-2020-3569","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:44+00:00","fetched_at":"2026-10-23T19:13:44+00:00","note":null},{"source":"nvd","external_id":"CVE-2020-3569","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-3569","severity":null,"published_at":"2020-09-23T01:15:15+00:00","modified_at":"2026-06-17T03:18:37+00:00","first_seen_at":"2026-10-23T21:57:35+00:00","fetched_at":"2026-10-23T21:57:35+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}