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Known Exploited Vulnerability
9.8
CRITICAL CVSS 3.1
CVE-2021-20090
Arcadyan Buffalo Firmware Path Traversal Vulnerability - [Actively Exploited]
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.

INFO

Published Date :

April 29, 2021, 3:15 p.m.

Last Modified :

March 19, 2025, 8:56 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
CISA Notification
CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

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.

Required Action :

Apply updates per vendor instructions.

Notes :

https://nvd.nist.gov/vuln/detail/CVE-2021-20090

Affected Products

The following products are affected by CVE-2021-20090 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Buffalo wsr-2533dhpl2-bk_firmware
2 Buffalo wsr-2533dhp3-bk_firmware
3 Buffalo wsr-2533dhpl2-bk
4 Buffalo wsr-2533dhp3-bk
: Total Affected Vendor : 1 | Products : 4
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 HIGH [email protected]
CVSS 3.1 CRITICAL [email protected]
CVSS 3.1 CRITICAL 134c704f-9b21-4f2e-91b3-4a467353bcc0
Solution
To address the path traversal vulnerability, update the device firmware.
  • Contact the vendor for the latest firmware update.
  • Apply the appropriate firmware update for the device.
Public PoC/Exploit Available at Github

CVE-2021-20090 has a 9 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-20090.

URL Resource
https://www.kb.cert.org/vuls/id/914124 Third 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-2021-13 Exploit Third Party Advisory
https://www.kb.cert.org/vuls/id/914124 Third 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-2021-13 Exploit Third Party Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-20090 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-20090 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
XiaomingX/awesome-poc-for-red-team

A curated collection of Proof of Concept (PoC) tools, scripts, and techniques designed for red team operations, penetration testing, and cybersecurity research. This repository focuses on providing practical resources for exploring vulnerabilities

attack cybersecurity exp hw penetration-testing poc red-team security-tools vulnerability-poc

Updated: 7 months, 1 week ago
5 stars 3 fork 3 watcher
Born at : Nov. 17, 2024, 11:53 a.m. This repo has been linked 414 different CVEs too.
Profile Photo
DinoBytes/RVASec-2024-Consumer-Routers-Still-Suck

Slides and other reference material for RVASec 2024 presentation

Updated: 1 year, 2 months ago
4 stars 0 fork 0 watcher
Born at : May 31, 2024, 8:23 p.m. This repo has been linked 5 different CVEs too.
Profile Photo
d4n-sec/d4n-sec.github.io

None

CSS HTML JavaScript

Updated: 1 year, 7 months ago
0 stars 0 fork 0 watcher
Born at : Feb. 2, 2024, 2:11 p.m. This repo has been linked 494 different CVEs too.
Profile Photo
ArrestX/--POC

poc集合(持续更新ing)

Updated: 2 months, 2 weeks ago
3 stars 0 fork 0 watcher
Born at : July 30, 2023, 1:30 a.m. This repo has been linked 154 different CVEs too.
Profile Photo
0day404/vulnerability-poc

A Common Vulnerability PoC Knowledge Base一个普遍漏洞POC知识库

vulnerability

Updated: 3 months, 2 weeks ago
21 stars 6 fork 6 watcher
Born at : June 24, 2023, 3:12 p.m. This repo has been linked 232 different CVEs too.
Profile Photo
34zY/APT-Backpack

cve-2019-11510, cve-2019-19781, cve-2020-5902,               cve-2021-1497, cve-2021-20090, cve-2021-22006, cve-2021-22205, cve-2021-26084, cve-2021-26855, cve-2021-26857, cve-2021–26857, cve-2021–26858, cve-2021–26865

Updated: 9 months, 4 weeks ago
3 stars 1 fork 1 watcher
Born at : Dec. 13, 2022, 8:41 a.m. This repo has been linked 21 different CVEs too.
Profile Photo
Ostorlab/KEV

Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

cisa-kev vulnerability 0day cisa exploits

Updated: 3 weeks, 5 days ago
581 stars 42 fork 42 watcher
Born at : April 19, 2022, 8:58 a.m. This repo has been linked 1287 different CVEs too.
Profile Photo
Threekiii/Awesome-POC

一个漏洞 PoC 知识库。A knowledge base for vulnerability PoCs(Proof of Concept), with 1k+ vulnerabilities.

poc

Dockerfile

Updated: 1 week, 2 days ago
4489 stars 899 fork 899 watcher
Born at : Feb. 20, 2022, 6:43 a.m. This repo has been linked 456 different CVEs too.
Profile Photo
ARPSyndicate/kenzer-templates

essential templates for kenzer [DEPRECATED]

kenzer vulnerabilities kenzer-templates arpsyndicate

Python Shell Ruby

Updated: 2 months ago
117 stars 38 fork 38 watcher
Born at : Sept. 18, 2020, 9:03 p.m. This repo has been linked 1655 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-20090 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2021-20090 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Modified Analysis by [email protected]

    Mar. 19, 2025

    Action Type Old Value New Value
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Feb. 06, 2025

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Added CWE CWE-22
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://www.kb.cert.org/vuls/id/914124
    Added Reference https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/
    Added Reference https://www.tenable.com/security/research/tra-2021-13
  • Modified Analysis by [email protected]

    Jul. 25, 2024

    Action Type Old Value New Value
    Changed Reference Type https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/ No Types Assigned https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/ Exploit, Third Party Advisory
    Changed CPE Configuration AND OR cpe:2.3:h:buffalo:wsr-2533dhpl2-bk:-:*:*:*:*:*:*:* OR *cpe:2.3:o:buffalo:wsr-2533dhpl2-bk_firmware:*:*:*:*:*:*:*:* versions up to (including) 1.02 AND OR *cpe:2.3:o:buffalo:wsr-2533dhpl2-bk_firmware:*:*:*:*:*:*:*:* versions up to (including) 1.02 OR cpe:2.3:h:buffalo:wsr-2533dhpl2-bk:-:*:*:*:*:*:*:*
    Changed CPE Configuration AND OR cpe:2.3:h:buffalo:wsr-2533dhp3-bk:-:*:*:*:*:*:*:* OR *cpe:2.3:o:buffalo:wsr-2533dhp3-bk_firmware:*:*:*:*:*:*:*:* versions up to (including) 1.24 AND OR *cpe:2.3:o:buffalo:wsr-2533dhp3-bk_firmware:*:*:*:*:*:*:*:* versions up to (including) 1.24 OR cpe:2.3:h:buffalo:wsr-2533dhp3-bk:-:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Oct. 18, 2023

    Action Type Old Value New Value
    Added Reference https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/ [No Types Assigned]
  • Modified Analysis by [email protected]

    Apr. 26, 2022

    Action Type Old Value New Value
    Changed Reference Type https://www.kb.cert.org/vuls/id/914124 No Types Assigned https://www.kb.cert.org/vuls/id/914124 Third Party Advisory, US Government Resource
    Changed Reference Type https://www.tenable.com/security/research/tra-2021-13 Third Party Advisory https://www.tenable.com/security/research/tra-2021-13 Exploit, Third Party Advisory
  • CVE Modified by [email protected]

    Jul. 20, 2021

    Action Type Old Value New Value
    Added Reference https://www.kb.cert.org/vuls/id/914124 [No Types Assigned]
  • Initial Analysis by [email protected]

    May. 08, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:P/A:P)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Changed Reference Type https://www.tenable.com/security/research/tra-2021-13 No Types Assigned https://www.tenable.com/security/research/tra-2021-13 Third Party Advisory
    Added CWE NIST CWE-22
    Added CPE Configuration AND OR *cpe:2.3:o:buffalo:wsr-2533dhpl2-bk_firmware:*:*:*:*:*:*:*:* versions up to (including) 1.02 OR cpe:2.3:h:buffalo:wsr-2533dhpl2-bk:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:buffalo:wsr-2533dhp3-bk_firmware:*:*:*:*:*:*:*:* versions up to (including) 1.24 OR cpe:2.3:h:buffalo:wsr-2533dhp3-bk:-:*:*:*:*:*:*:*
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 9.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 7.5
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

94.40 }} 0.03%

score

0.99968

percentile