{"id":"CVE-2026-19601","kind":"vulnerability","aliases":["CVE-2026-19601"],"related":[],"title":"Mattermost: stored AD/LDAP bind password leaks to attacker-chosen server","description":"Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to invalidate the stored AD/LDAP bind password when other connection settings (such as the server address) are changed, which allows a System Console administrator to disclose the plaintext bind password to an attacker-controlled server via the Test Connection / diagnostics feature. Mattermost Advisory ID: MMSA-2026-00764","summary":"Mattermost keeps the AD/LDAP bind password after other connection settings, such as the server address, are changed. A System Console administrator can then use Test Connection to send that plaintext password to a server they control.","severity":"medium","cvss":4.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["active-directory","ldap","mattermost","package","self-hosted"],"not_affected_if":["auth-required","managed-hosting","no-ad-ldap"],"how_to_check":"- Check the Mattermost server version with `mattermost version` or the System Console version page; affected lines are 11.7.x up to 11.7.10, 11.8.x up to 11.8.5, 11.9.x up to 11.9.1, and 11.10.x up to 11.10.1\n- Confirm AD/LDAP is enabled in System Console under Authentication > AD/LDAP","fix":"- Upgrade Mattermost to a fixed release for your line (unknown exact version in sources; see MMSA-2026-00764)\n- Rotate the AD/LDAP bind password after upgrading, since it may already have been exposed","status":"open","published_at":"2026-10-16T07:17:12+00:00","first_seen_at":"2026-10-23T21:57:12+00:00","triaged_at":"2026-10-25T04:32:56+00:00","updated_at":"2026-10-25T04:32:56+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-25T04:32:56Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Mattermost to a fixed release for your line (unknown exact version in sources; see MMSA-2026-00764)\n- Rotate the AD/LDAP bind password after upgrading, since it may already have been exposed","reach":"network","title":"Mattermost: stored AD/LDAP bind password leaks to attacker-chosen server","impact":"medium","summary":"Mattermost keeps the AD/LDAP bind password after other connection settings, such as the server address, are changed. A System Console administrator can then use Test Connection to send that plaintext password to a server they control.","category":"package","nicknames":[],"who_cares":["mattermost","self-hosted","ldap","active-directory"],"confidence":0.7,"needs_auth":"yes","worst_case":"Attacker learns the plaintext AD/LDAP bind password via a rogue server","analyst_note":"Find the fixed version numbers for each release line in MMSA-2026-00764 (Mattermost advisory) and confirm the Test Connection path.","how_to_check":"- Check the Mattermost server version with `mattermost version` or the System Console version page; affected lines are 11.7.x up to 11.7.10, 11.8.x up to 11.8.5, 11.9.x up to 11.9.1, and 11.10.x up to 11.10.1\n- Confirm AD/LDAP is enabled in System Console under Authentication > AD/LDAP","needs_analyst":true,"not_affected_if":["managed-hosting","no-ad-ldap","auth-required"],"who_is_affected":"Self-hosted Mattermost deployments on the listed affected versions that use AD/LDAP login with a bind account. The attacker must already hold a System Console administrator role. Teams on managed hosting, unaffected versions, or without AD/LDAP can skip it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000672,"input_tokens":3430,"output_tokens":657,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-00764':125C '-19601':14A,17A '-2026':13A,16A,124C '11.10':74C '11.10.1':76C '11.7':71C '11.7.10':73C '11.8':68C '11.8.5':70C '11.9':65C '11.9.1':67C 'activ':19B 'active-directori':18B 'ad/ldap':3A,30B,82C 'address':41B,93C 'administr':47B,101C 'advisori':121C 'allow':97C 'attack':9A,111C 'attacker-chosen':8A 'attacker-control':110C 'bind':4A,31B,83C,106C 'chang':43B,95C 'chosen':10A 'connect':35B,52B,87C,117C 'consol':46B,100C 'control':62B,112C 'cve':12A,15A 'diagnost':118C 'directori':20B 'disclos':103C 'fail':77C 'featur':119C 'host':26B 'id':122C 'invalid':79C 'keep':28B 'ldap':21B 'leak':6A 'mattermost':1A,22B,27B,63C,120C 'mmsa':123C 'packag':23B 'password':5A,32B,57B,84C,107C 'plaintext':56B,105C 'self':25B 'self-host':24B 'send':54B 'server':11A,40B,60B,92C,113C 'set':36B,88C 'store':2A,81C 'system':45B,99C 'test':51B,116C 'use':50B 'version':64C 'via':114C 'x':66C,69C,72C,75C","nicknames":[],"mitigations":[],"who_affected":"Self-hosted Mattermost deployments on the listed affected versions that use AD/LDAP login with a bind account. The attacker must already hold a System Console administrator role. Teams on managed hosting, unaffected versions, or without AD/LDAP can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-16T07:17:12+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N","cvss_by":"responsibledisclosure@mattermost.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-19601","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19601","severity":null,"published_at":"2026-10-16T07:17:12+00:00","modified_at":"2026-10-16T19:23:18+00:00","first_seen_at":"2026-10-23T21:57:12+00:00","fetched_at":"2026-10-23T22:28:55+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"}