{"id":"CVE-2021-34203","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-34203","generatedAt":"2026-10-28T02:59:02.178Z","title":"D-Link DIR-2640-US 1.01B04 is vulnerable to Incorrect Access Control.","description":"D-Link DIR-2640-US 1.01B04 is vulnerable to Incorrect Access Control. Router ac2600 (dir-2640-us), when setting PPPoE, will start quagga process in the way of whole network monitoring, and this function uses the original default password and port. An attacker can easily use telnet to log in, modify routing information, monitor the traffic of all devices under the router, hijack DNS and phishing attacks. In addition, this interface is likely to be questioned by customers as a backdoor, because the interface should not be exposed.","published":"2021-06-16T20:15:08.000Z","lastModified":"2026-07-09T01:16:56.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"cwe":["CWE-1188"],"affected":["dlink/dir-2640-us firmware"],"epss":{"score":0.01195,"percentile":0.67841,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (1.20%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/liyansong2018/CVE/tree/main/2021/CVE-2021-34203","tags":["Exploit","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.dlink.com/en/security-bulletin/","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/liyansong2018/CVE/tree/main/2021/CVE-2021-34203","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.dlink.com/en/security-bulletin/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-34203","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}