{"id":"CVE-2026-20127","kind":"vulnerability","aliases":["CVE-2026-20127"],"related":[],"title":"A vulnerability in the peering authentication in Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, Cisco…","description":"Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, and Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, contain an authentication bypass vulnerability could allow an unauthenticated, remote attacker to bypass authentication and obtain administrative privileges on an affected system. This vulnerability exists because the peering authentication mechanism in an affected system is not working properly. An attacker could exploit this vulnerability by sending crafted requests to an affected system. A successful exploit could allow the attacker to log in to an affected Cisco Catalyst SD-WAN Controller as an internal, high-privileged, non-root user account. Using this account, the attacker could access NETCONF, which would then allow the attacker to manipulate network configuration for the SD-WAN fabric.\n\nCISA required action: Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlines in CISA’s Emergency Directive 26-03 (URL listed below in Notes) and CISA’s “Hunt & Hardening Guidance for Cisco SD-WAN Devices (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.","summary":"Cisco Catalyst SD-WAN Controller and Manager have an authentication bypass in their peering authentication mechanism. A remote attacker with no credentials can gain administrative access and manipulate SD-WAN fabric network configuration through NETCONF.","severity":"critical","cvss":10.0,"epss":null,"exploited":true,"exploited_at":"2026-02-25T00:00:00+00:00","products":[{"name":"Cisco Catalyst SD-WAN Controller and Manager","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"cisco catalyst sd-wan manager","fixed":["20.9.8.2"],"affected":"< 20.9.8.2","ecosystem":"vendor"},{"name":"cisco catalyst sd-wan manager","fixed":["20.12.5.3"],"affected":">= 20.11, < 20.12.5.3","ecosystem":"vendor"},{"name":"cisco catalyst sd-wan manager","fixed":["20.15.4.2"],"affected":">= 20.13, < 20.15.4.2","ecosystem":"vendor"},{"name":"cisco catalyst sd-wan manager","fixed":["20.18.2.1"],"affected":">= 20.16, < 20.18.2.1","ecosystem":"vendor"},{"name":"cisco catalyst sd-wan manager","fixed":[],"affected":"= 20.12.6","ecosystem":"vendor"},{"name":"cisco sd-wan vbond orchestrator","fixed":["20.9.8.2"],"affected":"< 20.9.8.2","ecosystem":"vendor"},{"name":"cisco sd-wan vbond orchestrator","fixed":["20.12.5.3"],"affected":">= 20.11, < 20.12.5.3","ecosystem":"vendor"},{"name":"cisco sd-wan vbond orchestrator","fixed":["20.15.4.2"],"affected":">= 20.13, < 20.15.4.2","ecosystem":"vendor"},{"name":"cisco sd-wan vbond orchestrator","fixed":["20.18.2.1"],"affected":">= 20.16, < 20.18.2.1","ecosystem":"vendor"},{"name":"cisco sd-wan vbond orchestrator","fixed":[],"affected":"= 20.12.6","ecosystem":"vendor"},{"name":"cisco sd-wan vsmart controller","fixed":["20.9.8.2"],"affected":"< 20.9.8.2","ecosystem":"vendor"},{"name":"cisco sd-wan vsmart controller","fixed":["20.12.5.3"],"affected":">= 20.11, < 20.12.5.3","ecosystem":"vendor"},{"name":"cisco sd-wan vsmart controller","fixed":["20.15.4.2"],"affected":">= 20.13, < 20.15.4.2","ecosystem":"vendor"},{"name":"cisco sd-wan vsmart controller","fixed":["20.18.2.1"],"affected":">= 20.16, < 20.18.2.1","ecosystem":"vendor"},{"name":"cisco sd-wan vsmart controller","fixed":[],"affected":"= 20.12.6","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["cisco","exploited","infrastructure","network-appliance","sd-wan","self-hosted"],"not_affected_if":[],"how_to_check":"Check the Cisco advisory and CISA Emergency Directive 26-03 and Hunt & Hardening Guidance for Cisco SD-WAN Devices, which the KEV entry references; the sources do not give specific commands or settings.","fix":"Apply the fixed release named in the Cisco advisory and follow CISA guidance to hunt for compromise and harden devices; the sources do not name a fixed version.","status":"open","published_at":"2026-02-25T00:00:00+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T20:42:11+00:00","updated_at":"2026-10-23T23:44:51+00:00","category":"infrastructure","confidence":0.7,"triage":{"at":"2026-10-23T20:42:11Z","model":"claude-haiku-5-5","output":{"fix":"Apply the fixed release named in the Cisco advisory and follow CISA guidance to hunt for compromise and harden devices; the sources do not name a fixed version.","reach":"internet","summary":"Cisco Catalyst SD-WAN Controller and Manager have an authentication bypass in their peering authentication mechanism. A remote attacker with no credentials can gain administrative access and manipulate SD-WAN fabric network configuration through NETCONF.","category":"infrastructure","who_cares":["cisco","sd-wan","self-hosted","network-appliance"],"confidence":0.7,"needs_auth":"no","worst_case":"Unauthenticated attacker gains administrative control and can alter SD-WAN fabric configuration.","analyst_note":"Find affected and fixed versions and the hunt steps in the Cisco advisory and CISA ED 26-03 guidance; the signal lists products as unknown affected/fixed.","how_to_check":"Check the Cisco advisory and CISA Emergency Directive 26-03 and Hunt & Hardening Guidance for Cisco SD-WAN Devices, which the KEV entry references; the sources do not give specific commands or settings.\nunknown","needs_analyst":true,"not_affected_if":[],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.000525,"input_tokens":2905,"output_tokens":468,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-01':361C '-03':332C '-20127':22A,25A '-2026':21A,24A '22':360C '26':331C 'access':162B,284C 'account':277C,280C 'action':304C 'adher':306C,355C 'administr':161B,212C 'affect':216C,228C,246C,260C 'allow':202C,252C,289C 'and':32A 'applianc':129B 'applic':358C 'assess':312C 'associ':317C 'attack':155B,206C,235C,254C,282C,291C 'authent':6A,146B,151B,198C,209C,224C 'avail':376C 'bod':359C 'bypass':147B,199C,208C 'catalyst':9A,27A,35A,41A,47A,53A,59A,137B,174C,186C,262C 'cisa':302C,308C,327C,339C 'cisco':8A,19A,26A,34A,40A,46A,52A,58A,64A,70A,76A,82A,88A,94A,100A,106A,112A,118A,124B,136B,173C,185C,261C,319C,345C 'cloud':364C 'configur':170B,295C 'contain':196C 'control':13A,141B,178C,266C 'controller':31A,99A,105A,111A,117A,123A 'could':201C,236C,251C,283C 'craft':242C 'credenti':158B 'cve':20A,23A 'devic':323C,349C 'direct':330C 'discontinu':367C 'emerg':329C 'exist':220C 'exploit':125B,237C,250C 'exposur':313C 'fabric':168B,301C 'former':14A,179C,191C 'gain':160B 'guidanc':343C,362C 'guidelin':310C 'harden':342C 'high':271C 'high-privileg':270C 'host':135B 'hunt':341C 'infrastructur':126B 'intern':269C 'list':334C,351C 'log':256C 'manag':143B,190C 'manager':33A,39A,45A,51A,57A,63A 'manipul':164B,293C 'mechan':152B,225C 'mitig':315C,373C 'netconf':172B,285C 'network':128B,169B,294C 'network-appli':127B 'non':274C 'non-root':273C 'note':337C,354C 'obtain':211C 'orchestrator':69A,75A,81A,87A,93A 'outlin':325C 'peer':5A,150B,223C 'pleas':305C 'privileg':213C,272C 'product':371C 'proper':233C 'remot':154B,205C 'request':243C 'requir':303C 'risk':316C 'root':275C 'sd':11A,16A,29A,37A,43A,49A,55A,61A,66A,72A,78A,84A,90A,96A,102A,108A,114A,120A,131B,139B,166B,176C,181C,188C,193C,264C,299C,321C,347C 'sd-wan':10A,15A,28A,36A,42A,48A,54A,60A,65A,71A,77A,83A,89A,95A,101A,107A,113A,119A,130B,138B,165B,175C,180C,187C,192C,263C,298C,320C,346C 'self':134B 'self-host':133B 'send':241C 'servic':365C 'success':249C 'system':217C,229C,247C 'unauthent':204C 'url':333C,350C 'use':278C,368C 'user':276C 'vbond':68A,74A,80A,86A,92A 'vmanag':195C 'vsmart':18A,98A,104A,110A,116A,122A,183C 'vulner':2A,200C,219C,239C 'wan':12A,17A,30A,38A,44A,50A,56A,62A,67A,73A,79A,85A,91A,97A,103A,109A,115A,121A,132B,140B,167B,177C,182C,189C,194C,265C,300C,322C,348C 'work':232C 'would':287C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2026-02-25T00:00:00+00:00","kev":{"dateAdded":"2026-02-25","dueDate":"2026-02-27","requiredAction":"Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlines in CISA’s Emergency Directive 26-03 (URL listed below in Notes) and CISA’s “Hunt & Hardening Guidance for Cisco SD-WAN Devices (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","cvss_by":"psirt@cisco.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2026-20127","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-20127","severity":null,"published_at":"2026-02-25T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T16:39:45+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-20127","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-20127","severity":null,"published_at":"2026-02-25T17:25:29+00:00","modified_at":"2026-06-17T15:06:12+00:00","first_seen_at":"2026-10-23T23:44:51+00:00","fetched_at":"2026-10-23T23:44:51+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"}