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

CVE-2021-20090 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 100.0%.

Is there a public PoC exploit available for CVE-2021-20090?

Yes, a public proof-of-concept exploit is available for CVE-2021-20090. Prioritise patching immediately. EPSS: 100.0%.

Wsr 2533Dhpl2 Bk Firmware CVE-2021-20090

CRITICAL

Path Traversal (CWE-22)

2021-04-29 vulnreport@tenable.com

Path Traversal Wsr 2533Dhpl2 Bk Firmware Wsr 2533Dhp3 Bk Firmware

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Added to CISA KEV

Jul 14, 2026 - 04:22 CISA

CVE Published

Apr 29, 2021 - 15:15 nvd

CRITICAL 9.8

DescriptionNVD

AnalysisAI

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. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Path Traversal (CWE-22), which allows attackers to access files and directories outside the intended path. 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. Affected products include: Buffalo Wsr-2533Dhpl2-Bk Firmware, Buffalo Wsr-2533Dhp3-Bk Firmware.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate and canonicalize file paths. Use chroot or sandboxing. Reject input containing path separators or '../' sequences.