{"id":"CVE-2026-17202","kind":"vulnerability","aliases":["CVE-2026-17202"],"related":[],"title":"IBM API Connect: login responses let attackers enumerate valid usernames","description":"IBM API Connect 12.1.0.0 through 12.1.1.2 could allow a remote attacker to enumerate usernames due to observable differences in response behavior.","summary":"IBM API Connect 12.1.0.0 through 12.1.1.2 returns observably different responses depending on whether a username exists. A remote attacker can use this to build a list of valid usernames for later password guessing or phishing.","severity":"medium","cvss":5.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["api-gateway","ibm-api-connect","runtime","self-hosted"],"not_affected_if":["outside-affected-versions"],"how_to_check":"- Check the installed IBM API Connect version against the affected range 12.1.0.0 through 12.1.1.2.","fix":null,"status":"open","published_at":"2026-11-07T05:18:30+00:00","first_seen_at":"2026-11-07T05:46:00+00:00","triaged_at":"2026-11-07T05:54:12+00:00","updated_at":"2026-11-07T05:54:12+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-07T05:54:12Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"internet","title":"IBM API Connect: login responses let attackers enumerate valid usernames","impact":"low","summary":"IBM API Connect 12.1.0.0 through 12.1.1.2 returns observably different responses depending on whether a username exists. A remote attacker can use this to build a list of valid usernames for later password guessing or phishing.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["ibm-api-connect","api-gateway","self-hosted"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"attacker gets valid usernames for password attacks","analyst_note":"Find the IBM security bulletin for CVE-2026-17202 to confirm affected endpoints, default config and the fixed version.","how_to_check":"- Check the installed IBM API Connect version against the affected range 12.1.0.0 through 12.1.1.2.\n- unknown","plain_action":"","needs_analyst":true,"not_affected_if":["outside-affected-versions"],"who_is_affected":"Teams running IBM API Connect 12.1.0.0 through 12.1.1.2 with a reachable login or user-facing endpoint are exposed. The sources do not say which endpoints leak the difference or whether a default configuration is affected. Deployments outside that version range can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000673,"input_tokens":4191,"output_tokens":507,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-17202':13A,16A '-2026':12A,15A '12.1.0.0':31B,66C '12.1.1.2':33B,68C 'allow':70C 'api':2A,18B,22B,29B,64C 'api-gateway':17B 'attack':7A,46B,73C 'behavior':83C 'build':51B 'connect':3A,23B,30B,65C 'could':69C 'cve':11A,14A 'depend':38B 'differ':36B,80C 'due':77C 'enumer':8A,75C 'exist':43B 'gateway':19B 'guess':60B 'host':27B 'ibm':1A,21B,28B,63C 'ibm-api-connect':20B 'later':58B 'let':6A 'list':53B 'login':4A 'observ':35B,79C 'password':59B 'phish':62B 'remot':45B,72C 'respons':5A,37B,82C 'return':34B 'runtim':24B 'self':26B 'self-host':25B 'use':48B 'usernam':10A,42B,56B,76C 'valid':9A,55B 'whether':40B","nicknames":[],"mitigations":[],"who_affected":"Teams running IBM API Connect 12.1.0.0 through 12.1.1.2 with a reachable login or user-facing endpoint are exposed. The sources do not say which endpoints leak the difference or whether a default configuration is affected. Deployments outside that version range can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["apigateway","ibmapiconnect","medium","runtime","selfhosted"],"campaign_type":null,"search_a":"'-17202':13A,16A '-2026':12A,15A 'api':2A 'attack':7A 'connect':3A 'cve':11A,14A 'enumer':8A 'ibm':1A 'let':6A 'login':4A 'respons':5A 'usernam':10A 'valid':9A","search_b":"'12.1.0.0':31B '12.1.1.2':33B 'api':18B,22B,29B 'api-gateway':17B 'attack':46B 'build':51B 'connect':23B,30B 'depend':38B 'differ':36B 'exist':43B 'gateway':19B 'guess':60B 'host':27B 'ibm':21B,28B 'ibm-api-connect':20B 'later':58B 'list':53B 'observ':35B 'password':59B 'phish':62B 'remot':45B 'respons':37B 'return':34B 'runtim':24B 'self':26B 'self-host':25B 'use':48B 'usernam':42B,56B 'valid':55B 'whether':40B","search_c":"'12.1.0.0':66C '12.1.1.2':68C 'allow':70C 'api':64C 'attack':73C 'behavior':83C 'connect':65C 'could':69C 'differ':80C 'due':77C 'enumer':75C 'ibm':63C 'observ':79C 'remot':72C 'respons':82C 'usernam':76C","first_public_at":"2026-11-07T05:18:30+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","cvss_by":"psirt@us.ibm.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-17202","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-17202","severity":null,"published_at":"2026-11-07T05:18:30+00:00","modified_at":"2026-11-07T05:18:30+00:00","first_seen_at":"2026-11-07T05:46:00+00:00","fetched_at":"2026-11-07T05:46:00+00:00","note":null}],"documents":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}