VULNERABILITY INTELLIGENCE

CVE-2021-20134

CVSS score8.4 HIGH
EPSS probability7.77%
CISA KEVNot currently listed
Published2021-12-30
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

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.

Weakness classification

  • CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Primary references