CVE-2021-20134
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (7.77%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.4 HIGHCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 7.77% probability · 95th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-22
- Affected
- dlink/dir-2640-us firmware
- Source
- vulnreport@tenable.com
EPSS 7.8% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://www.tenable.com/security/research/tra-2021-44Exploit, Third Party Advisory
- https://www.tenable.com/security/research/tra-2021-44Exploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.