CVE-2021-34203
D-Link DIR-2640-US 1.01B04 is vulnerable to Incorrect Access Control.
Does this matter?
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.
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.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 1.20% probability · 68th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-1188
- Affected
- dlink/dir-2640-us firmware
- Source
- cve@mitre.org
EPSS 1.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/liyansong2018/CVE/tree/main/2021/CVE-2021-34203Exploit, Third Party Advisory
- https://www.dlink.com/en/security-bulletin/Vendor Advisory
- https://github.com/liyansong2018/CVE/tree/main/2021/CVE-2021-34203Exploit, Third Party Advisory
- https://www.dlink.com/en/security-bulletin/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.