What is the CVSS score of CVE-2021-20134?

CVE-2021-20134 has a CVSS 3.1 base score of 8.4 (High). CVSS vector: CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 7.5%.

Is there a public PoC exploit available for CVE-2021-20134?

Yes, a public proof-of-concept exploit is available for CVE-2021-20134. Prioritise patching immediately. EPSS: 7.5%.

Dir 2640 Us Firmware CVE-2021-20134

HIGH

Path Traversal (CWE-22)

2021-12-30 vulnreport@tenable.com

D-Link RCE Path Traversal Dir 2640 Us Firmware

8.4

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.4 HIGH

AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

CVE Published

Dec 30, 2021 - 22:15 nvd

HIGH 8.4

DescriptionNVD

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.

AnalysisAI

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. Rated high severity (CVSS 8.4), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Path Traversal (CWE-22), which allows attackers to access files and directories outside the intended path. 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 include: Dlink Dir-2640-Us Firmware. Version information: version 1.11.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate and canonicalize file paths. Use chroot or sandboxing. Reject input containing path separators or '../' sequences.