Actively exploited in the wild
Arcadyan Buffalo Firmware Path Traversal Vulnerability
Arcadyan - Buffalo Firmware · Listed in the CISA KEV since 2021-11-03. This indicates confirmed attacks in production environments.
Required action: Apply updates per vendor instructions.
CVE-2021-20090
CriticalCVSS 9.8KEVSummary
A path traversal vulnerability in the web interfaces of Buffalo WSR-2533DHPL2 firmware version <= 1.02 and WSR-2533DHP3 firmware version <= 1.24 could allow unauthenticated remote attackers to bypass authentication.
Risk Assessment
An attacker with network access to the router's web interface can gain unauthorized access to the administrative panel without credentials. This may lead to full compromise of the device and the network behind it.
Recommendation
Update the firmware of Buffalo WSR-2533DHPL2 and WSR-2533DHP3 routers to the latest version provided by the vendor. Until patched, restrict access to the router's web interface to trusted networks only.
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Original NVD description (English source)
A path traversal vulnerability in the web interfaces of Buffalo WSR-2533DHPL2 firmware version <= 1.02 and WSR-2533DHP3 firmware version <= 1.24 could allow unauthenticated remote attackers to bypass authentication.