{"id":"CVE-2026-12489","kind":"vulnerability","aliases":["CVE-2026-12489"],"related":[],"title":"Zyxel EX3501-T0 firmware: authenticated users can escalate privileges via login_privilege","description":"An incorrect authorization vulnerability in the Data Access Layer (DAL) of Zyxel EX3501-T0 firmware versions through 5.44(ACHR.6)C0 could allow an authenticated attacker to escalate privileges by modifying the login_privilege data on an affected device.","summary":"An incorrect authorization flaw in the Data Access Layer of Zyxel EX3501-T0 firmware up to 5.44(ACHR.6)C0 lets a logged-in user change the login_privilege data. That lets the attacker raise their own privileges on the device.","severity":"medium","cvss":6.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["firmware","infrastructure","network-gear","zyxel"],"not_affected_if":["newer-firmware","other-zyxel-models"],"how_to_check":"- Check the installed firmware version on the device (unknown exact command or menu path in the sources)\n- Compare the version against `5.44(ACHR.6)C0` and earlier builds listed as affected","fix":"- Update the EX3501-T0 firmware to a version newer than `5.44(ACHR.6)C0` (the fixed version is unknown from the sources)","status":"open","published_at":"2026-10-20T03:17:15+00:00","first_seen_at":"2026-10-23T21:57:19+00:00","triaged_at":"2026-10-25T03:55:42+00:00","updated_at":"2026-10-25T03:55:42+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-25T03:55:42Z","model":"claude-haiku-5-5","output":{"fix":"- Update the EX3501-T0 firmware to a version newer than `5.44(ACHR.6)C0` (the fixed version is unknown from the sources)","reach":"unknown","title":"Zyxel EX3501-T0 firmware: authenticated users can escalate privileges via login_privilege","impact":"medium","summary":"An incorrect authorization flaw in the Data Access Layer of Zyxel EX3501-T0 firmware up to 5.44(ACHR.6)C0 lets a logged-in user change the login_privilege data. That lets the attacker raise their own privileges on the device.","category":"infrastructure","nicknames":[],"who_cares":["zyxel","network-gear","firmware"],"confidence":0.6,"needs_auth":"yes","worst_case":"Low-privileged user gains higher device privileges","analyst_note":"Check Zyxel's advisory for the fixed firmware version and whether the flaw is reachable from the network or only from the local UI.","how_to_check":"- Check the installed firmware version on the device (unknown exact command or menu path in the sources)\n- Compare the version against `5.44(ACHR.6)C0` and earlier builds listed as affected","needs_analyst":true,"not_affected_if":["other-zyxel-models","newer-firmware"],"who_is_affected":"Owners of Zyxel EX3501-T0 devices running firmware through `5.44(ACHR.6)C0`. The attacker must already hold a valid login on the device. Devices with no user accounts beyond the administrator have a smaller exposure, but the sources do not say more.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000623,"input_tokens":3325,"output_tokens":580,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-12489':16A,19A '-2026':15A,18A '5.44':43B,86C 'access':33B,75C 'achr.6':44B,87C 'affect':105C 'allow':90C 'attack':60B,93C 'authent':6A,92C 'author':28B,70C 'c0':45B,88C 'chang':52B 'could':89C 'cve':14A,17A 'dal':77C 'data':32B,56B,74C,102C 'devic':67B,106C 'escal':9A,95C 'ex3501':3A,38B,81C 'ex3501-t0':2A,37B,80C 'firmwar':5A,20B,40B,83C 'flaw':29B 'gear':24B 'incorrect':27B,69C 'infrastructur':21B 'layer':34B,76C 'let':46B,58B 'log':49B 'logged-in':48B 'login':12A,54B,100C 'modifi':98C 'network':23B 'network-gear':22B 'privileg':10A,13A,55B,64B,96C,101C 'rais':61B 't0':4A,39B,82C 'user':7A,51B 'version':84C 'via':11A 'vulner':71C 'zyxel':1A,25B,36B,79C","nicknames":[],"mitigations":[],"who_affected":"Owners of Zyxel EX3501-T0 devices running firmware through `5.44(ACHR.6)C0`. The attacker must already hold a valid login on the device. Devices with no user accounts beyond the administrator have a smaller exposure, but the sources do not say more.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T03:17:15+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","cvss_by":"security@zyxel.com.tw","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-12489","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-12489","severity":null,"published_at":"2026-10-20T03:17:15+00:00","modified_at":"2026-10-21T04:18:10+00:00","first_seen_at":"2026-10-23T21:57:19+00:00","fetched_at":"2026-10-23T22:28:57+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"}