{"id":"CVE-2026-126129","kind":"vulnerability","aliases":["CVE-2026-126129"],"related":[],"title":"Auth0 ASP.NET Core SDK: logged-out sessions may still reach protected endpoints","description":"The Auth0 ASP.NET Core Authentication SDK incorrectly determines a session's OIDC Back-Channel Logout status, which may result in a logged-out session being accepted for access to protected endpoints.","summary":"The Auth0 ASP.NET Core Authentication SDK wrongly decides whether a session has been ended by OIDC Back-Channel Logout. A logged-out session can therefore still be accepted for protected endpoints.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["asp.net-core","auth0","nuget","oidc","package"],"not_affected_if":["no-back-channel-logout"],"how_to_check":"- Confirm the project references the Auth0 ASP.NET Core Authentication SDK (NuGet package `Auth0.AspNetCore.Authentication`) and note its version.\n- Check whether the app uses OIDC Back-Channel Logout.","fix":null,"status":"open","published_at":"2026-11-10T22:18:31+00:00","first_seen_at":"2026-11-10T22:27:30+00:00","triaged_at":"2026-11-10T22:31:10+00:00","updated_at":"2026-11-10T22:31:10+00:00","category":"package","confidence":0.5,"triage":{"at":"2026-11-10T22:31:10Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"internet","title":"Auth0 ASP.NET Core SDK: logged-out sessions may still reach protected endpoints","impact":"medium","summary":"The Auth0 ASP.NET Core Authentication SDK wrongly decides whether a session has been ended by OIDC Back-Channel Logout. A logged-out session can therefore still be accepted for protected endpoints.","audience":"developers","category":"package","nicknames":[],"who_cares":["auth0","asp.net-core","nuget","oidc"],"confidence":0.5,"fix_status":"unknown","needs_auth":"unknown","worst_case":"logged-out sessions gain access to protected endpoints","analyst_note":"Find the affected and fixed SDK versions and the exact back-channel logout conditions in the NVD entry or the Auth0 advisory.","how_to_check":"- Confirm the project references the Auth0 ASP.NET Core Authentication SDK (NuGet package `Auth0.AspNetCore.Authentication`) and note its version.\n- Check whether the app uses OIDC Back-Channel Logout.\n- unknown for the affected version range; the sources do not list it.","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-back-channel-logout"],"who_is_affected":"Applications built on the Auth0 ASP.NET Core Authentication SDK that rely on OIDC Back-Channel Logout to end sessions are the ones at risk, since a session that should be logged out may still be accepted. Apps that do not use back-channel logout are likely not exposed, but the sources do not confirm the exact conditions.","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000753,"input_tokens":4526,"output_tokens":600,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-126129':16A,19A '-2026':15A,18A 'accept':55B,86C 'access':88C 'asp.net':2A,20B,28B,61C 'auth0':1A,22B,27B,60C 'authent':30B,63C 'back':43B,72C 'back-channel':42B,71C 'channel':44B,73C 'core':3A,21B,29B,62C 'cve':14A,17A 'decid':33B 'determin':66C 'end':39B 'endpoint':13A,58B,91C 'incorrect':65C 'log':6A,48B,82C 'logged-out':5A,47B,81C 'logout':45B,74C 'may':9A,77C 'nuget':23B 'oidc':24B,41B,70C 'packag':25B 'protect':12A,57B,90C 'reach':11A 'result':78C 'sdk':4A,31B,64C 'session':8A,36B,50B,68C,84C 'status':75C 'still':10A,53B 'therefor':52B 'whether':34B 'wrong':32B","nicknames":[],"mitigations":[],"who_affected":"Applications built on the Auth0 ASP.NET Core Authentication SDK that rely on OIDC Back-Channel Logout to end sessions are the ones at risk, since a session that should be logged out may still be accepted. Apps that do not use back-channel logout are likely not exposed, but the sources do not confirm the exact conditions.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["aspnetcore","auth0","nuget","oidc","package","unknown"],"campaign_type":null,"search_a":"'-126129':16A,19A '-2026':15A,18A 'asp.net':2A 'auth0':1A 'core':3A 'cve':14A,17A 'endpoint':13A 'log':6A 'logged-out':5A 'may':9A 'protect':12A 'reach':11A 'sdk':4A 'session':8A 'still':10A","search_b":"'accept':55B 'asp.net':20B,28B 'auth0':22B,27B 'authent':30B 'back':43B 'back-channel':42B 'channel':44B 'core':21B,29B 'decid':33B 'end':39B 'endpoint':58B 'log':48B 'logged-out':47B 'logout':45B 'nuget':23B 'oidc':24B,41B 'packag':25B 'protect':57B 'sdk':31B 'session':36B,50B 'still':53B 'therefor':52B 'whether':34B 'wrong':32B","search_c":"'accept':86C 'access':88C 'asp.net':61C 'auth0':60C 'authent':63C 'back':72C 'back-channel':71C 'channel':73C 'core':62C 'determin':66C 'endpoint':91C 'incorrect':65C 'log':82C 'logged-out':81C 'logout':74C 'may':77C 'oidc':70C 'protect':90C 'result':78C 'sdk':64C 'session':68C,84C 'status':75C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T22:18:31+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-126129","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-126129","severity":null,"published_at":"2026-11-10T22:18:31+00:00","modified_at":"2026-11-10T22:18:31+00:00","first_seen_at":"2026-11-10T22:27:30+00:00","fetched_at":"2026-11-10T22:27:30+00:00","note":null}],"documents":[],"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"}