{"id":"CVE-2020-12812","kind":"vulnerability","aliases":["CVE-2020-12812"],"related":[],"title":"Fortinet FortiOS: Fortinet FortiOS SSL VPN Improper Authentication Vulnerability","description":"Fortinet FortiOS SSL VPN contains an improper authentication vulnerability that may allow a user to login successfully without being prompted for the second factor of authentication (FortiToken) if they change the case in their username.\n\nCISA required action: Apply updates per vendor instructions.","summary":"Fortinet FortiOS SSL VPN can let a user log in without the second factor (FortiToken) when the username's letter case is changed. An attacker with a valid username and password gets VPN access without the one-time code.","severity":"critical","cvss":9.8,"epss":0.45379,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Fortinet FortiOS","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","fortios","fortitoken","infrastructure","ransomware","ssl-vpn"],"not_affected_if":["no-fortitoken-2fa","no-ssl-vpn"],"how_to_check":null,"fix":"Apply the FortiOS update per Fortinet's vendor instructions; the sources do not name the fixed version.","status":"open","published_at":"2020-07-24T23:15:12+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:33:37+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-23T21:33:37Z","model":"claude-haiku-5-5","output":{"fix":"Apply the FortiOS update per Fortinet's vendor instructions; the sources do not name the fixed version.\nunknown","reach":"internet","impact":"high","summary":"Fortinet FortiOS SSL VPN can let a user log in without the second factor (FortiToken) when the username's letter case is changed. An attacker with a valid username and password gets VPN access without the one-time code.","category":"infrastructure","who_cares":["fortios","ssl-vpn","fortitoken"],"confidence":0.6,"needs_auth":"yes","worst_case":"Attacker with valid password gets VPN login without second factor","analyst_note":"Confirm affected and fixed FortiOS versions and the exact SSL VPN/FortiToken config from Fortinet's advisory (FG-IR-20-120); the sources give no version data.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["no-ssl-vpn","no-fortitoken-2fa"],"user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000473,"input_tokens":2864,"output_tokens":373,"severity_before":"unknown"},"analyst_status":"queued","analyst_note":"Confirm affected and fixed FortiOS versions and the exact SSL VPN/FortiToken config from Fortinet's advisory (FG-IR-20-120); the sources give no version data.","search":"'-12812':12A,15A '-2020':11A,14A 'access':59B 'action':103C 'allow':77C 'appli':104C 'attack':50B 'authent':8A,73C,91C 'case':46B,97C 'chang':48B,95C 'cisa':101C 'code':65B 'contain':70C 'cve':10A,13A 'exploit':18B 'factor':39B,89C 'fortinet':1A,3A,16A,26B,66C 'fortio':2A,4A,19B,27B,67C 'fortios':17A 'fortitoken':20B,40B,92C 'get':57B 'improp':7A,72C 'infrastructur':21B 'instruct':108C 'let':31B 'letter':45B 'log':34B 'login':81C 'may':76C 'one':63B 'one-tim':62B 'password':56B 'per':106C 'prompt':85C 'ransomwar':22B 'requir':102C 'second':38B,88C 'ssl':5A,24B,28B,68C 'ssl-vpn':23B 'success':82C 'time':64B 'updat':105C 'user':33B,79C 'usernam':43B,54B,100C 'valid':53B 'vendor':107C 'vpn':6A,25B,29B,58B,69C 'vulner':9A,74C 'without':36B,60B,83C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2020-07-24T23:15:12+00:00","kev":{"dateAdded":"2021-11-03","dueDate":"2022-05-03","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Known"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2020-12812","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-12812","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":"2026-10-25T13:39:32+00:00","note":null},{"source":"epss","external_id":"CVE-2020-12812","url":"https://api.first.org/data/v1/epss?cve=CVE-2020-12812","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-2020-12812","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-12812","severity":null,"published_at":"2020-07-24T23:15:12+00:00","modified_at":"2026-10-02T14:54:53+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"}