How severe is CVE-2021-20739?

CVE-2021-20739 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-20739 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20739?

CVE-2021-20739 primarily affects Elecom Wrc-300febk Firmware. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20739?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-20739 published?

CVE-2021-20739 was published on 2021-07-07 and last updated on 2026-06-17.

CVE-2021-20739

CVE-2021-20739 is a high-severity vulnerability in Elecom Wrc-300febk Firmware with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 5.8
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Elecom Wrc-300febk Firmware
Published: 2021-07-07
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-20739?: 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.
How severe is CVE-2021-20739?: CVE-2021-20739 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-20739 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20739?: CVE-2021-20739 primarily affects Elecom Wrc-300febk Firmware. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20739?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-20739 published?: CVE-2021-20739 was published on 2021-07-07 and last updated on 2026-06-17.

References

Affected products (11)

cpe:2.3:o:elecom:wrc-300febk_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrc-f300nf_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrc-733febk_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrh-300rd_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrh-300bk_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrh-300sv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrh-300wh_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrh-h300wh_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrh-h300bk_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrh-300bk-s_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:elecom:wrh-300wh-s_firmware:*:*:*:*:*:*:*:*

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