{"id":"CVE-2026-123521","kind":"vulnerability","aliases":["CVE-2026-123521"],"related":[],"title":"Vikunja: missing rate limit lets session holders brute-force passwords and disable TOTP","description":"Vikunja before 2.7.1 contains an improper restriction of excessive authentication attempts vulnerability that allows session holders to brute-force account passwords via unthrottled re-authentication endpoints. Attackers with a stolen session can guess the password via /user/settings/totp/disable without lockout, then disable TOTP without a code for persistent account takeover.","summary":"Vikunja, an open-source task manager, does not limit failed attempts on its re-authentication endpoint for disabling two-factor login (TOTP). An attacker holding a stolen session can guess the account password without lockout, then turn off TOTP and keep access to the account.","severity":"medium","cvss":6.0,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["package","self-hosted","totp","vikunja"],"not_affected_if":["version-2.7.1-or-later"],"how_to_check":"- Check the Vikunja version with the server's version endpoint or the running image tag; compare it to `2.7.1`.\n- Look for the `/user/settings/totp/disable` route in your deployed build's API.","fix":"- Vikunja: upgrade to `2.7.1` or later.","status":"open","published_at":"2026-11-08T02:16:41+00:00","first_seen_at":"2026-11-08T02:21:09+00:00","triaged_at":"2026-11-08T02:25:10+00:00","updated_at":"2026-11-08T02:25:10+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-08T02:25:10Z","model":"claude-haiku-5-5","output":{"fix":"- Vikunja: upgrade to `2.7.1` or later.","reach":"network","title":"Vikunja: missing rate limit lets session holders brute-force passwords and disable TOTP","impact":"high","summary":"Vikunja, an open-source task manager, does not limit failed attempts on its re-authentication endpoint for disabling two-factor login (TOTP). An attacker holding a stolen session can guess the account password without lockout, then turn off TOTP and keep access to the account.","audience":"businesses","category":"package","nicknames":[],"who_cares":["vikunja","self-hosted","totp"],"confidence":0.7,"fix_status":"available","needs_auth":"yes","worst_case":"attacker keeps persistent account access after disabling two-factor login","analyst_note":"","how_to_check":"- Check the Vikunja version with the server's version endpoint or the running image tag; compare it to `2.7.1`.\n- Look for the `/user/settings/totp/disable` route in your deployed build's API.","plain_action":"","needs_analyst":false,"not_affected_if":["version-2.7.1-or-later"],"who_is_affected":"Teams that self-host or run Vikunja below `2.7.1`. An attacker needs an already-valid session token, such as one stolen from a browser or device, so the risk is limited to accounts with a live session. Instances that run only the latest release, or that do not use TOTP, are less exposed to the takeover path.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000696,"input_tokens":4285,"output_tokens":534,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-123521':17A,20A '-2026':16A,19A '/user/settings/totp/disable':113C '2.7.1':77C 'access':71B 'account':61B,74B,95C,124C 'allow':88C 'attack':53B,103C 'attempt':38B,85C 'authent':43B,84C,101C 'brute':9A,93C 'brute-forc':8A,92C 'code':121C 'contain':78C 'cve':15A,18A 'disabl':13A,46B,117C 'endpoint':44B,102C 'excess':83C 'factor':49B 'fail':37B 'forc':10A,94C 'guess':59B,109C 'hold':54B 'holder':7A,90C 'host':24B 'improp':80C 'keep':70B 'let':5A 'limit':4A,36B 'lockout':64B,115C 'login':50B 'manag':33B 'miss':2A 'open':30B 'open-sourc':29B 'packag':21B 'password':11A,62B,96C,111C 'persist':123C 'rate':3A 're':42B,100C 're-authent':41B,99C 'restrict':81C 'self':23B 'self-host':22B 'session':6A,57B,89C,107C 'sourc':31B 'stolen':56B,106C 'takeov':125C 'task':32B 'totp':14A,25B,51B,68B,118C 'turn':66B 'two':48B 'two-factor':47B 'unthrottl':98C 'via':97C,112C 'vikunja':1A,26B,27B,75C 'vulner':86C 'without':63B,114C,119C","nicknames":[],"mitigations":[],"who_affected":"Teams that self-host or run Vikunja below `2.7.1`. An attacker needs an already-valid session token, such as one stolen from a browser or device, so the risk is limited to accounts with a live session. Instances that run only the latest release, or that do not use TOTP, are less exposed to the takeover path.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["medium","package","selfhosted","totp","vikunja"],"campaign_type":null,"search_a":"'-123521':17A,20A '-2026':16A,19A 'brute':9A 'brute-forc':8A 'cve':15A,18A 'disabl':13A 'forc':10A 'holder':7A 'let':5A 'limit':4A 'miss':2A 'password':11A 'rate':3A 'session':6A 'totp':14A 'vikunja':1A","search_b":"'access':71B 'account':61B,74B 'attack':53B 'attempt':38B 'authent':43B 'disabl':46B 'endpoint':44B 'factor':49B 'fail':37B 'guess':59B 'hold':54B 'host':24B 'keep':70B 'limit':36B 'lockout':64B 'login':50B 'manag':33B 'open':30B 'open-sourc':29B 'packag':21B 'password':62B 're':42B 're-authent':41B 'self':23B 'self-host':22B 'session':57B 'sourc':31B 'stolen':56B 'task':32B 'totp':25B,51B,68B 'turn':66B 'two':48B 'two-factor':47B 'vikunja':26B,27B 'without':63B","search_c":"'/user/settings/totp/disable':113C '2.7.1':77C 'account':95C,124C 'allow':88C 'attack':103C 'attempt':85C 'authent':84C,101C 'brute':93C 'brute-forc':92C 'code':121C 'contain':78C 'disabl':117C 'endpoint':102C 'excess':83C 'forc':94C 'guess':109C 'holder':90C 'improp':80C 'lockout':115C 'password':96C,111C 'persist':123C 're':100C 're-authent':99C 'restrict':81C 'session':89C,107C 'stolen':106C 'takeov':125C 'totp':118C 'unthrottl':98C 'via':97C,112C 'vikunja':75C 'vulner':86C 'without':114C,119C","first_public_at":"2026-10-22T10:06:49+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-123521","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123521","severity":null,"published_at":"2026-11-08T02:16:41+00:00","modified_at":"2026-11-08T02:16:41+00:00","first_seen_at":"2026-11-08T02:21:09+00:00","fetched_at":"2026-11-08T02:21:09+00:00","note":null}],"documents":[{"id":99191,"url":"https://github.com/go-vikunja/vikunja/security/advisories/GHSA-49pj-52x6-8gpj","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-22T10:06:49+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":99192,"url":"https://www.vulncheck.com/advisories/vikunja-before-2.7.1-password-brute-force-via-totp-disable-endpoint","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}