Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-20090

CVE-2021-20090CRITICAL

n/a Buffalo WSR-2533DHPL2, Buffalo WSR-2533DHP3 — Arcadyan Buffalo Firmware

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS    %ile   KEV
   N   L   N   N  U  H  H  H    9.8   .9998   100.0   YES

AFFECTED
  Product                                      Versions                                      Fixed
  Buffalo WSR-2533DHPL2, Buffalo WSR-2533DHP3  WSR-2533DHPL2 <=1.02, WSR-2533DHP3 <= 1.24 –  —

TIMELINE
  Dec 17  Reserved by tenable
  Apr 29  Published (CNA: tenable)
  Nov 3   Added to CISA KEV, remediation due 2021-11-17

CWE-22 · CNA: tenable · CVSS v3.1 · 4 references · KEV due November 17, 2021

Description

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
December 17, 2020	Reserved	Reserved by tenable
April 29, 2021	Published	Published (CNA: tenable)
November 3, 2021	KEV ADDED	Added to CISA KEV, remediation due 2021-11-17

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	Buffalo WSR-2533DHPL2, Buffalo WSR-2533DHP3	—	WSR-2533DHPL2 <=1.02, WSR-2533DHP3 <= 1.24	—

Weaknesses

CWE-22

References (4)

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20090 [government-resource]
https://www.kb.cert.org/vuls/id/914124 [third-party-advisory]
https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/
https://www.tenable.com/security/research/tra-2021-13

Authoritative record: CVE-2021-20090 at cve.org

Weaknesses: CWE-22

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-20090 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.