CVE-2021-3512

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-04-28 · updated 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.

Affected products

Buffalo Bhr-4Grv Firmware: before 2.00 — fixed in 2.00
Buffalo Dwr-Hp-G300Nh Firmware: before 1.84 — fixed in 1.84
Buffalo Fs-600Dhp Firmware: before 3.40 — fixed in 3.40
Buffalo Fs-G300N Firmware: before 3.14 — fixed in 3.14
Buffalo Fs-Hp-G300N Firmware: before 3.33 — fixed in 3.33
Buffalo Fs-R600Dhp Firmware: before 3.40 — fixed in 3.40
Buffalo Hw-450Hp-Zwe Firmware: before 2.00 — fixed in 2.00
Buffalo Whr-300 Firmware: before 2.00 — fixed in 2.00
Buffalo Whr-300Hp Firmware: before 2.00 — fixed in 2.00
Buffalo Whr-G301N Firmware: before 1.87 — fixed in 1.87
Buffalo Whr-Hp-G300N Firmware: before 2.00 — fixed in 2.00
Buffalo Whr-Hp-Gn Firmware: before 1.87 — fixed in 1.87
Buffalo Wpl-05G300 Firmware: before 1.88 — fixed in 1.88
Buffalo Wzr-300Hp Firmware: before 2.00 — fixed in 2.00
Buffalo Wzr-450Hp-Cwt Firmware: before 2.00 — fixed in 2.00
Buffalo Wzr-450Hp-Ub Firmware: before 2.00 — fixed in 2.00
Buffalo Wzr-450Hp Firmware: before 2.00 — fixed in 2.00
Buffalo Wzr-600Dhp Firmware: before 2.00 — fixed in 2.00
Buffalo Wzr-D1100H Firmware: before 2.00 — fixed in 2.00
Buffalo Wzr-Hp-Ag300H Firmware: before 1.76 — fixed in 1.76
Buffalo Wzr-Hp-G300Nh Firmware: before 1.84 — fixed in 1.84
Buffalo Wzr-Hp-G301Nh Firmware: before 1.84 — fixed in 1.84
Buffalo Wzr-Hp-G302H Firmware: before 1.86 — fixed in 1.86
Buffalo Wzr-Hp-G450H Firmware: before 1.90 — fixed in 1.90

How to fix

Upgrade to a fixed version: Buffalo Bhr-4Grv Firmware 2.00; Buffalo Dwr-Hp-G300Nh Firmware 1.84; Buffalo Fs-600Dhp Firmware 3.40; Buffalo Fs-G300N Firmware 3.14; Buffalo Fs-Hp-G300N Firmware 3.33; Buffalo Fs-R600Dhp Firmware 3.40; Buffalo Hw-450Hp-Zwe Firmware 2.00; Buffalo Whr-300 Firmware 2.00; Buffalo Whr-300Hp Firmware 2.00; Buffalo Whr-G301N Firmware 1.87; Buffalo Whr-Hp-G300N Firmware 2.00; Buffalo Whr-Hp-Gn Firmware 1.87. Check the vendor advisory for mitigations.

References

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