{"id":"CVE-2026-116516","kind":"vulnerability","aliases":["CVE-2026-116516"],"related":[],"title":"Mattermost: Zoom chat parsing flaw lets a user crash the Agents plugin","description":"Mattermost versions <=11.9 11.1.9 11.5.8 11.10.7.0 fail to validate Zoom chat line length before slicing which allows an authenticated attacker to crash the Agents plugin via summarizing a Zoom chat transcription containing short continuation lines. Mattermost Advisory ID: MMSA-2026-00723","summary":"Mattermost versions up to 11.9 and several 11.x builds fail to check the length of Zoom chat lines before slicing them. An authenticated user who summarizes a Zoom chat transcription with short continuation lines can crash the Agents plugin.","severity":"medium","cvss":6.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["agents-plugin","mattermost","package","self-hosted","zoom"],"not_affected_if":["no-agents-plugin","no-zoom-integration"],"how_to_check":"- Check the Mattermost server version against the affected list (<=11.9, 11.1.9, 11.5.8, 11.10.7.0) and confirm whether the Agents plugin is installed\n- unknown: the sources do not say which exact builds are vulnerable beyond the listed versions","fix":"- Upgrade Mattermost to a fixed release listed in the advisory (MMSA-2026-00723), such as `11.10.7.0` or later in the 11.10 line, `11.5.8` or later in the 11.5 line, or `11.1.9` or later in the 11.1 line\n- unknown: the sources do not name the exact patched Agents plugin version","status":"open","published_at":"2026-10-26T14:16:37+00:00","first_seen_at":"2026-10-26T14:30:37+00:00","triaged_at":"2026-10-26T14:32:33+00:00","updated_at":"2026-10-26T14:32:33+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-26T14:32:33Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Mattermost to a fixed release listed in the advisory (MMSA-2026-00723), such as `11.10.7.0` or later in the 11.10 line, `11.5.8` or later in the 11.5 line, or `11.1.9` or later in the 11.1 line\n- unknown: the sources do not name the exact patched Agents plugin version","reach":"network","title":"Mattermost: Zoom chat parsing flaw lets a user crash the Agents plugin","impact":"low","summary":"Mattermost versions up to 11.9 and several 11.x builds fail to check the length of Zoom chat lines before slicing them. An authenticated user who summarizes a Zoom chat transcription with short continuation lines can crash the Agents plugin.","category":"package","nicknames":[],"who_cares":["mattermost","self-hosted","agents-plugin","zoom"],"confidence":0.6,"needs_auth":"yes","worst_case":"Agents plugin crashes, disrupting summarization for the server","analyst_note":"","how_to_check":"- Check the Mattermost server version against the affected list (<=11.9, 11.1.9, 11.5.8, 11.10.7.0) and confirm whether the Agents plugin is installed\n- unknown: the sources do not say which exact builds are vulnerable beyond the listed versions","needs_analyst":false,"not_affected_if":["no-agents-plugin","no-zoom-integration"],"who_is_affected":"Teams running self-hosted Mattermost in the affected version ranges that have the Agents plugin enabled and use Zoom chat transcription summarization. Instances without the Agents plugin or without Zoom transcription summarization are not exposed to this flaw.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000648,"input_tokens":3349,"output_tokens":626,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-00723':108C '-116516':15A,18A '-2026':14A,17A,107C '11':35B '11.1.9':71C '11.10.7.0':73C '11.5.8':72C '11.9':32B,70C 'advisori':104C 'agent':11A,20B,66B,91C 'agents-plugin':19B 'allow':84C 'attack':87C 'authent':51B,86C 'build':37B 'chat':3A,45B,57B,78C,97C 'check':40B 'contain':99C 'continu':61B,101C 'crash':9A,64B,89C 'cve':13A,16A 'fail':38B,74C 'flaw':5A 'host':26B 'id':105C 'length':42B,80C 'let':6A 'line':46B,62B,79C,102C 'mattermost':1A,22B,28B,68C,103C 'mmsa':106C 'packag':23B 'pars':4A 'plugin':12A,21B,67B,92C 'self':25B 'self-host':24B 'sever':34B 'short':60B,100C 'slice':48B,82C 'summar':54B,94C 'transcript':58B,98C 'user':8A,52B 'valid':76C 'version':29B,69C 'via':93C 'x':36B 'zoom':2A,27B,44B,56B,77C,96C","nicknames":[],"mitigations":[],"who_affected":"Teams running self-hosted Mattermost in the affected version ranges that have the Agents plugin enabled and use Zoom chat transcription summarization. Instances without the Agents plugin or without Zoom transcription summarization are not exposed to this flaw.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-26T14:16:37+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvss_by":"responsibledisclosure@mattermost.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-116516","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-116516","severity":null,"published_at":"2026-10-26T14:16:37+00:00","modified_at":"2026-10-26T14:16:37+00:00","first_seen_at":"2026-10-26T14:30:37+00:00","fetched_at":"2026-10-26T14:30:37+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"}