Is CVE-2021-20090 actively exploited?

Yes. CVE-2021-20090 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, which means exploitation in the wild has been confirmed.

Can CVE-2021-20090 be exploited remotely?

The attack vector of CVE-2021-20090 has not been classified yet.

What is the CVSS score of CVE-2021-20090?

CVE-2021-20090 has not received a CVSS score yet.

HOME VULNERABILITIESCVE-2021-20090

HIGHCISA KEVIN THE WILD

CVE-2021-20090

Published: November 3, 2021

EPSS:94.40%probability of exploitation in 30 daysPercentile:100.0th

Official Description

Arcadyan Buffalo firmware contains a path traversal vulnerability that could allow unauthenticated, remote attackers to bypass authentication and access sensitive information. This vulnerability affects multiple routers across several different vendors.

NVD Source

CISA KEV Advisory

Arcadyan Buffalo Firmware Path Traversal Vulnerability

Added to KEV: 2021-11-03Federal patch deadline: 2021-11-17

Required Action (CISA)

Apply updates per vendor instructions.

Risk Analysis

This path traversal vulnerability in Arcadyan Buffalo firmware allows unauthenticated, remote attackers to bypass authentication and access sensitive information. The very high EPSS score indicates a strong likelihood of exploitation, and its inclusion in CISA's KEV confirms active exploitation, making this a critical threat.

Active exploitation of this vulnerability has been observed in the wild, indicating that working exploits are readily available and being used by attackers. This flaw is remotely exploitable.

Recommended Action

Update affected routers from various vendors using Arcadyan Buffalo firmware to the latest secure versions. Restrict network access to these devices and ensure they are not directly exposed to the internet.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2021-20090 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

CISA has added CVE-2021-20090 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.