What’s Vulnerable › Vulnerabilities

CVE-2021-20134

• Severity: high (CVSS 8.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 7.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-12-30 · updated 2026-06-17
• Weakness: CWE-22

Description

Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 are affected by an absolute path traversal vulnerability that allows a remote, authenticated attacker to set an arbitrary file on the router's filesystem as the log file used by either Quagga service (zebra or ripd). Subsequent log messages will be appended to the file, prefixed by a timestamp and some logging metadata. Remote code execution can be achieved by using this vulnerability to append to a shell script on the router's filesystem, and then awaiting or triggering the execution of that script. A remote, unauthenticated root shell can easily be obtained on the device in this fashion.

Affected products

• Quagga Services on D-Link DIR-2640 Routers: through 1.11b02

References

• https://www.tenable.com/security/research/tra-2021-44
• https://www.tenable.com/security/research/tra-2021-44

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