What’s Vulnerable › Vulnerabilities

CVE-2021-34203

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-06-16 · updated 2026-07-09
• Weakness: CWE-1188

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.

Affected products

• Quagga Services on D-Link DIR-2640 Routers: 1.01b04

References

• https://github.com/liyansong2018/CVE/tree/main/2021/CVE-2021-34203
• https://www.dlink.com/en/security-bulletin/
• https://github.com/liyansong2018/CVE/tree/main/2021/CVE-2021-34203
• https://www.dlink.com/en/security-bulletin/

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