Is CVE-2021-20739 actively exploited?

No active exploitation of CVE-2021-20739 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-20739 be exploited remotely?

Partially. CVE-2021-20739 requires adjacent network access (same network segment) to exploit.

What is the CVSS score of CVE-2021-20739?

CVE-2021-20739 has a CVSS score of 8.8 (HIGH).

HOME VULNERABILITIESCVE-2021-20739

HIGH

CVE-2021-20739

CWE-78Published: July 7, 2021· Updated: Jun 17, 2026

8.8

CVSS v3.1

Official Description

WRC-300FEBK, WRC-F300NF, WRC-733FEBK, WRH-300RD, WRH-300BK, WRH-300SV, WRH-300WH, WRH-H300WH, WRH-H300BK, WRH-300BK-S, and WRH-300WH-S all versions allows an unauthenticated network-adjacent attacker to execute an arbitrary OS command via unspecified vectors.

NVD Source

Technical Analysis

CVE-2021-20739 requires adjacent network access, limiting remote exploitation but still posing risk in shared or local network environments.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorAdjacent

Attack ComplexityLow

Privileges Req.None

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Affected Vendors & Products

elecom22 product(s)

wrc-300febk firmwarewrc-300febkwrc-f300nf firmwarewrc-f300nfwrc-733febk firmwarewrc-733febkwrh-300rd firmwarewrh-300rdwrh-300bk firmwarewrh-300bkwrh-300sv firmwarewrh-300sv+10

Source: NVD CPE · 22 total CPE entries