{"id":"CVE-2026-107146","kind":"vulnerability","aliases":["CVE-2026-107146"],"related":[],"title":"Roundcube 2FA plugin: failed verification leaves session alive for attacker","description":"The twofactor_gauthenticator plugin for Roundcube is vulnerable to session persistence after failed 2FA verification. Due to the lack of server-side session destruction, an attacker can ignore the logout redirect and keep the session alive. This may allow an attacker who obtains user's password to e.g. brute force the second-factor code.\n\n\n\n\nThis issue was fixed in commit 4640889.","summary":"The twofactor_gauthenticator plugin for Roundcube does not destroy the server-side session after a failed second-factor check, so the session stays valid. An attacker who already has the user's password can keep that session and keep guessing the second-factor code.","severity":"medium","cvss":6.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["package","roundcube","self-hosted","two-factor-auth","webmail"],"not_affected_if":["no-2fa-enabled","plugin-not-installed"],"how_to_check":"- Check whether the installed Roundcube has the twofactor_gauthenticator plugin enabled in `config/config.inc.php` under `plugins`\n- Compare the plugin source against upstream commit `4640889`; the sources do not name a fixed release version","fix":"- Update the twofactor_gauthenticator plugin to a release that includes commit `4640889`; the sources do not name the version\n- unknown for any other configuration change","status":"open","published_at":"2026-10-27T10:16:54+00:00","first_seen_at":"2026-10-27T10:31:02+00:00","triaged_at":"2026-10-27T10:31:58+00:00","updated_at":"2026-10-27T10:31:58+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-27T10:31:58Z","model":"claude-haiku-5-5","output":{"fix":"- Update the twofactor_gauthenticator plugin to a release that includes commit `4640889`; the sources do not name the version\n- unknown for any other configuration change","reach":"internet","title":"Roundcube 2FA plugin: failed verification leaves session alive for attacker","impact":"medium","summary":"The twofactor_gauthenticator plugin for Roundcube does not destroy the server-side session after a failed second-factor check, so the session stays valid. An attacker who already has the user's password can keep that session and keep guessing the second-factor code.","category":"package","nicknames":[],"who_cares":["roundcube","self-hosted","webmail","two-factor-auth"],"confidence":0.6,"needs_auth":"yes","worst_case":"Attacker with password keeps session and brute-forces second-factor code","analyst_note":"Confirm the first fixed plugin release version and the affected version range from the upstream commit 4640889 or the plugin repository.","how_to_check":"- Check whether the installed Roundcube has the twofactor_gauthenticator plugin enabled in `config/config.inc.php` under `plugins`\n- Compare the plugin source against upstream commit `4640889`; the sources do not name a fixed release version","needs_analyst":true,"not_affected_if":["plugin-not-installed","no-2fa-enabled"],"who_is_affected":"Roundcube installations that use the twofactor_gauthenticator plugin for two-factor login are exposed. Sites without this plugin, or that do not enable two-factor authentication through it, can skip it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000619,"input_tokens":3346,"output_tokens":569,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-107146':13A,16A '-2026':12A,15A '2fa':2A,87C '4640889':136C 'aliv':8A,110C 'allow':113C 'alreadi':56B 'attack':10A,54B,100C,115C 'auth':25B 'brute':123C 'check':47B 'code':73B,129C 'commit':135C 'cve':11A,14A 'destroy':35B 'destruct':98C 'due':89C 'e.g':122C 'factor':24B,46B,72B,128C 'fail':4A,43B,86C 'fix':133C 'forc':124C 'gauthent':29B,76C 'guess':68B 'host':21B 'ignor':102C 'issu':131C 'keep':63B,67B,107C 'lack':92C 'leav':6A 'logout':104C 'may':112C 'obtain':117C 'packag':17B 'password':61B,120C 'persist':84C 'plugin':3A,30B,77C 'redirect':105C 'roundcub':1A,18B,32B,79C 'second':45B,71B,127C 'second-factor':44B,70B,126C 'self':20B 'self-host':19B 'server':38B,95C 'server-sid':37B,94C 'session':7A,40B,50B,65B,83C,97C,109C 'side':39B,96C 'stay':51B 'two':23B 'two-factor-auth':22B 'twofactor':28B,75C 'user':59B,118C 'valid':52B 'verif':5A,88C 'vulner':81C 'webmail':26B","nicknames":[],"mitigations":[],"who_affected":"Roundcube installations that use the twofactor_gauthenticator plugin for two-factor login are exposed. Sites without this plugin, or that do not enable two-factor authentication through it, can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T10:16:54+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/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":"cvd@cert.pl","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-107146","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107146","severity":null,"published_at":"2026-10-27T10:16:54+00:00","modified_at":"2026-10-27T10:16:54+00:00","first_seen_at":"2026-10-27T10:31:02+00:00","fetched_at":"2026-10-27T10:31:02+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"}