{"id":"CVE-2026-42019","kind":"vulnerability","aliases":["CVE-2026-42019"],"related":[],"title":"Totolink X2000R router: stack overflow in IPv6 PPPoE setup lets attackers run code","description":"Multiple stack-based buffer overflow vulnerabilities exist in the boa formIpv6Setup pppoe functionality of Totolink X2000R TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327. A specially crafted HTTP request can lead to arbitrary code execution. An attacker can make an authenticated HTTP request to trigger these vulnerabilities. This vulnerability concerns the pppoe_dns1 parameter.","summary":"The web management interface (boa, formIpv6Setup) of the Totolink X2000R router has stack-based buffer overflows in its PPPoE settings, triggered through the pppoe_dns1 parameter. An attacker who is logged in to the admin interface can send a crafted HTTP request to run code on the router.","severity":"critical","cvss":9.1,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"X2000R","fixed":[],"affected":"TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327","ecosystem":"firmware"}],"ecosystems":[],"tags":["infrastructure","routers","self-hosted","totolink","x2000r"],"not_affected_if":["auth-required","other-models","remote-management-disabled"],"how_to_check":"Open the router admin page, Status/Firmware: version TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327 is affected. Also check whether the web UI answers from the WAN side.","fix":"No fixed firmware published as of 2026-10-23. Mitigate: turn off WAN/remote management of the admin UI, restrict it to a trusted LAN, change default admin credentials, and check totolink.tw/totolink.net X2000R support pages for new firmware.","status":"open","published_at":"2026-10-20T21:17:18+00:00","first_seen_at":"2026-10-23T21:57:21+00:00","triaged_at":"2026-10-23T22:39:10+00:00","updated_at":"2026-10-23T23:14:44+00:00","category":"infrastructure","confidence":0.7,"triage":{"at":"2026-10-23T22:39:10Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Totolink X2000R router: stack overflow in IPv6 PPPoE setup lets attackers run code","impact":"high","summary":"The web management interface (boa, formIpv6Setup) of the Totolink X2000R router has stack-based buffer overflows in its PPPoE settings, triggered through the pppoe_dns1 parameter. An attacker who is logged in to the admin interface can send a crafted HTTP request to run code on the router.","category":"infrastructure","who_cares":["totolink","x2000r","routers","self-hosted"],"confidence":0.6,"needs_auth":"yes","worst_case":"Code runs on the router after an authenticated crafted request.","analyst_note":"Find the vendor patched firmware version and advisory for X2000R; the NVD entry gives no fixed build or exploit status.","how_to_check":"Check the firmware version on the router admin page; the affected build is TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327 per the NVD description.\nunknown","needs_analyst":true,"not_affected_if":["other-models","auth-required"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.000516,"input_tokens":3003,"output_tokens":432,"severity_before":"critical"},"analyst_status":"done","analyst_note":"Find the vendor patched firmware version and advisory for X2000R; the NVD entry gives no fixed build or exploit status.","search":"'-2026':15A,18A '-42019':16A,19A '0.0':99C 'admin':63B 'arbitrari':109C 'attack':11A,56B,113C 'authent':117C 'b20250421.1327':100C 'base':42B,80C 'boa':32B,87C 'buffer':43B,81C 'code':13A,73B,110C 'concern':126C 'craft':68B,103C 'cve':14A,17A 'dns1':53B,129C 'execut':111C 'exist':84C 'formipv6setup':33B,88C 'function':90C 'gh':97C 'host':25B 'http':69B,104C,118C 'infrastructur':21B 'interfac':31B,64B 'ipv6':7A 'lead':107C 'let':10A 'log':59B 'make':115C 'manag':30B 'multipl':77C 'overflow':5A,44B,82C 'paramet':54B,130C 'pppoe':8A,47B,52B,89C,128C 'request':70B,105C,119C 'router':3A,22B,38B,76B 'run':12A,72B 'self':24B 'self-host':23B 'send':66B 'set':48B 'setup':9A 'special':102C 'stack':4A,41B,79C 'stack-bas':40B,78C 'totolink':1A,26B,36B,92C,95C 'totolink-x2000r-gh-v1':94C 'trigger':49B,121C 'v1':98C 'vulner':83C,123C,125C 'web':29B 'x2000r':2A,20A,27B,37B,93C,96C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T21:17:18+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","cvss_by":"talos-cna@cisco.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-42019","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42019","severity":null,"published_at":"2026-10-20T21:17:18+00:00","modified_at":"2026-10-22T15:31:24+00:00","first_seen_at":"2026-10-23T21:57:21+00:00","fetched_at":"2026-10-23T22:28:58+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-42019:397","url":null,"severity":null,"published_at":"2026-10-23T23:14:44+00:00","modified_at":"2026-10-23T23:14:44+00:00","first_seen_at":"2026-10-23T23:14:44+00:00","fetched_at":"2026-10-23T23:14:44+00:00","note":"No vendor advisory or fixed firmware found: TOTOLINK security bulletins list nothing for X2000R; only NVD and a RedTeam Monitor rewrite (no patch confirmed). No X posts, no public PoC found, no exploitation reported. Part of a batch of sibling X2000R boa CVEs."}],"documents":[{"id":1856,"url":"https://www.totolink.net/support/security-bulletins","title":"TOTOLINK security bulletins (no X2000R entry)","kind":"vendor","source":"analyst","text":null,"published_at":null,"relation":"mentions","confidence":null,"note":null},{"id":1858,"url":"https://redteammonitor.com/c/vulnerabilities/totolink-x2000r-firmware-v1-0-0-b20250421-1327/","title":"RedTeam Monitor: Totolink X2000R PPPoE flaws","kind":"blog","source":"analyst","text":null,"published_at":null,"relation":"describes","confidence":null,"note":null}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}