{"id":"CVE-2026-122020","kind":"vulnerability","aliases":["CVE-2026-122020"],"related":[],"title":"Nstbrowser: stopAll endpoint flaw lets remote users cause denial of service","description":"A security flaw has been discovered in NST Labs Tech Nstbrowser up to 1.2.1. The affected element is the function stopAllBrowsers of the file /api/agent/browser/stopAll of the component Local Agent Management Service. Performing a manipulation results in denial of service. Remote exploitation of the attack is possible. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.","summary":"Nstbrowser up to 1.2.1 has a flaw in the stopAllBrowsers function behind the /api/agent/browser/stopAll endpoint of its Local Agent Management Service. A remote attacker can manipulate it to cause a denial of service, and a public exploit has been released.","severity":"medium","cvss":5.0,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browser-automation","nstbrowser","other"],"not_affected_if":["unknown"],"how_to_check":"- Check whether Nstbrowser is installed and its version is `1.2.1` or lower\n- Check whether the Local Agent Management Service is reachable from the network: unknown","fix":null,"status":"open","published_at":"2026-11-04T22:17:56+00:00","first_seen_at":"2026-11-04T23:08:48+00:00","triaged_at":"2026-11-04T23:10:08+00:00","updated_at":"2026-11-04T23:10:08+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-11-04T23:10:08Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Nstbrowser: stopAll endpoint flaw lets remote users cause denial of service","impact":"low","summary":"Nstbrowser up to 1.2.1 has a flaw in the stopAllBrowsers function behind the /api/agent/browser/stopAll endpoint of its Local Agent Management Service. A remote attacker can manipulate it to cause a denial of service, and a public exploit has been released.","audience":"businesses","category":"other","nicknames":[],"who_cares":["nstbrowser","browser-automation"],"confidence":0.6,"fix_status":"unknown","needs_auth":"unknown","worst_case":"remote attacker crashes the browser automation service","analyst_note":"Confirm whether the Local Agent Management Service binds beyond localhost and whether any vendor fix exists; the NVD entry gives no fixed version.","how_to_check":"- Check whether Nstbrowser is installed and its version is `1.2.1` or lower\n- Check whether the Local Agent Management Service is reachable from the network: unknown","plain_action":"","needs_analyst":true,"not_affected_if":["unknown"],"who_is_affected":"Teams running Nstbrowser up to version 1.2.1 with its Local Agent Management Service exposed to remote callers. The sources do not say which configurations expose the endpoint, and the vendor did not respond to disclosure.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.00069,"input_tokens":4275,"output_tokens":524,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-122020':14A,17A '-2026':13A,16A '/api/agent/browser/stopall':35B,86C '1.2.1':25B,75C 'affect':77C 'agent':40B,91C 'attack':45B,106C,122C 'autom':20B 'behind':33B 'browser':19B 'browser-autom':18B 'caus':8A,50B 'compon':89C 'contact':126C 'cve':12A,15A 'denial':9A,52B,99C 'disclosur':130C 'discov':67C 'earli':127C 'element':78C 'endpoint':3A,36B 'exploit':58B,103C,110C 'file':85C 'flaw':4A,28B,64C 'function':32B,81C 'lab':70C 'let':5A 'local':39B,90C 'manag':41B,92C 'manipul':47B,96C 'may':118C 'nst':69C 'nstbrowser':1A,21B,22B,72C 'perform':94C 'possibl':108C 'public':57B,116C 'releas':61B,113C 'remot':6A,44B,102C 'respond':134C 'result':97C 'secur':63C 'servic':11A,42B,54B,93C,101C 'stopal':2A 'stopallbrows':31B,82C 'tech':71C 'use':120C 'user':7A 'vendor':124C 'way':137C","nicknames":[],"mitigations":[],"who_affected":"Teams running Nstbrowser up to version 1.2.1 with its Local Agent Management Service exposed to remote callers. The sources do not say which configurations expose the endpoint, and the vendor did not respond to disclosure.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["browserautomation","medium","nstbrowser","other"],"campaign_type":null,"first_public_at":"2026-11-04T22:17:56+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/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":"cna@vuldb.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-122020","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-122020","severity":null,"published_at":"2026-11-04T22:17:56+00:00","modified_at":"2026-11-04T22:17:56+00:00","first_seen_at":"2026-11-04T23:08:48+00:00","fetched_at":"2026-11-04T23:08:48+00:00","note":null}],"documents":[],"exploit_sources":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}