CVE-2021-20090

CriticalCVSS 9.8/10Known exploited (CISA KEV)Last modified Jun 17, 2026

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.

Metrics

CVSS 3.1 9.8/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-22

Affected software

Vendor	Product	Versions
n/a	Buffalo WSR-2533DHPL2, Buffalo WSR-2533DHP3	WSR-2533DHPL2 <=1.02, WSR-2533DHP3 <= 1.24

References

https://www.kb.cert.org/vuls/id/914124Third Party Advisory, US Government Resource
https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/Exploit, Third Party Advisory
https://www.tenable.com/security/research/tra-2021-13Exploit, Third Party Advisory
https://www.kb.cert.org/vuls/id/914124Third Party Advisory, US Government Resource
https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/Exploit, Third Party Advisory
https://www.tenable.com/security/research/tra-2021-13Exploit, Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20090US Government Resource

Timeline

Published: Apr 29, 2021
Last modified: Jun 17, 2026
Added to CISA KEV: Nov 3, 2021
NVD status: Analyzed

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