How severe is CVE-2021-3512?

CVE-2021-3512 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-2021-3512 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3512?

CVE-2021-3512 primarily affects Buffalo Bhr-4grv Firmware. In total, 24 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-3512?

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-2021-3512 published?

CVE-2021-3512 was published on 2021-04-28 and last updated on 2026-06-17.

CVE-2021-3512

CVE-2021-3512 is a high-severity vulnerability in Buffalo Bhr-4grv 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.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 8.3
EPSS exploit prediction: 1% (54th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Buffalo Bhr-4grv Firmware
Published: 2021-04-28
Last modified: 2026-06-17

Description

Improper access control vulnerability in Buffalo broadband routers (BHR-4GRV firmware Ver.1.99 and prior, DWR-HP-G300NH firmware Ver.1.83 and prior, HW-450HP-ZWE firmware Ver.1.99 and prior, WHR-300HP firmware Ver.1.99 and prior, WHR-300 firmware Ver.1.99 and prior, WHR-G301N firmware Ver.1.86 and prior, WHR-HP-G300N firmware Ver.1.99 and prior, WHR-HP-GN firmware Ver.1.86 and prior, WPL-05G300 firmware Ver.1.87 and prior, WZR-450HP-CWT firmware Ver.1.99 and prior, WZR-450HP-UB firmware Ver.1.99 and prior, WZR-HP-AG300H firmware Ver.1.75 and prior, WZR-HP-G300NH firmware Ver.1.83 and prior, WZR-HP-G301NH firmware Ver.1.83 and prior, WZR-HP-G302H firmware Ver.1.85 and prior, WZR-HP-G450H firmware Ver.1.89 and prior, WZR-300HP firmware Ver.1.99 and prior, WZR-450HP firmware Ver.1.99 and prior, WZR-600DHP firmware Ver.1.99 and prior, WZR-D1100H firmware Ver.1.99 and prior, FS-HP-G300N firmware Ver.3.32 and prior, FS-600DHP firmware Ver.3.38 and prior, FS-R600DHP firmware Ver.3.39 and prior, and FS-G300N firmware Ver.3.13 and prior) allows remote unauthenticated attackers to bypass access restriction and to start telnet service and execute arbitrary OS commands with root privileges via unspecified vectors.

Frequently asked questions

What is CVE-2021-3512?: Improper access control vulnerability in Buffalo broadband routers (BHR-4GRV firmware Ver.1.99 and prior, DWR-HP-G300NH firmware Ver.1.83 and prior, HW-450HP-ZWE firmware Ver.1.99 and prior, WHR-300HP firmware Ver.1.99 and prior, WHR-300 firmware Ver.1.99 and prior, WHR-G301N firmware Ver.1.86 and prior, WHR-HP-G300N firmware Ver.1.99 and prior, WHR-HP-GN firmware Ver.1.86 and prior, WPL-05G300 firmware Ver.1.87 and prior, WZR-450HP-CWT firmware Ver.1.99 and prior, WZR-450HP-UB firmware Ver.1.99 and prior, WZR-HP-AG300H firmware Ver.1.75 and prior, WZR-HP-G300NH firmware Ver.1.83 and prior, WZR-HP-G301NH firmware Ver.1.83 and prior, WZR-HP-G302H firmware Ver.1.85 and prior, WZR-HP-G450H firmware Ver.1.89 and prior, WZR-300HP firmware Ver.1.99 and prior, WZR-450HP firmware Ver.1.99 and prior, WZR-600DHP firmware Ver.1.99 and prior, WZR-D1100H firmware Ver.1.99 and prior, FS-HP-G300N firmware Ver.3.32 and prior, FS-600DHP firmware Ver.3.38 and prior, FS-R600DHP firmware Ver.3.39 and prior, and FS-G300N firmware Ver.3.13 and prior) allows remote unauthenticated attackers to bypass access restriction and to start telnet service and execute arbitrary OS commands with root privileges via unspecified vectors.
How severe is CVE-2021-3512?: CVE-2021-3512 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-2021-3512 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3512?: CVE-2021-3512 primarily affects Buffalo Bhr-4grv Firmware. In total, 24 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-3512?: 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-2021-3512 published?: CVE-2021-3512 was published on 2021-04-28 and last updated on 2026-06-17.

References

Affected products (24)

cpe:2.3:o:buffalo:bhr-4grv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:dwr-hp-g300nh_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:hw-450hp-zwe_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:whr-300hp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:whr-300_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:whr-g301n_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:whr-hp-g300n_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:whr-hp-gn_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wpl-05g300_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-450hp-cwt_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-450hp-ub_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-hp-ag300h_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-hp-g300nh_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-hp-g301nh_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-hp-g302h_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-hp-g450h_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-300hp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-450hp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-600dhp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wzr-d1100h_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:fs-hp-g300n_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:fs-600dhp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:fs-r600dhp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:fs-g300n_firmware:*:*:*:*:*:*:*:*

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