How severe is CVE-2021-20731?

CVE-2021-20731 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-2021-20731 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20731?

CVE-2021-20731 primarily affects Buffalo Wsr-1166dhp4 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20731?

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-2021-20731 published?

CVE-2021-20731 was published on 2021-06-09 and last updated on 2026-06-17.

CVE-2021-20731

CVE-2021-20731 is a high-severity vulnerability in Buffalo Wsr-1166dhp4 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: 8.3
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Buffalo Wsr-1166dhp4 Firmware
Published: 2021-06-09
Last modified: 2026-06-17

Description

WSR-1166DHP3 firmware Ver.1.16 and prior and WSR-1166DHP4 firmware Ver.1.02 and prior allow an attacker to execute arbitrary OS commands with root privileges via unspecified vectors.

Frequently asked questions

What is CVE-2021-20731?: WSR-1166DHP3 firmware Ver.1.16 and prior and WSR-1166DHP4 firmware Ver.1.02 and prior allow an attacker to execute arbitrary OS commands with root privileges via unspecified vectors.
How severe is CVE-2021-20731?: CVE-2021-20731 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-2021-20731 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20731?: CVE-2021-20731 primarily affects Buffalo Wsr-1166dhp4 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20731?: 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-2021-20731 published?: CVE-2021-20731 was published on 2021-06-09 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:buffalo:wsr-1166dhp4_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wsr-1166dhp3_firmware:*:*:*:*:*:*:*:*

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