How severe is CVE-2021-20091?

CVE-2021-20091 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-20091 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20091?

CVE-2021-20091 primarily affects Buffalo Wsr-2533dhpl2-bk Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20091?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-20091 published?

CVE-2021-20091 was published on 2021-04-29 and last updated on 2026-06-17.

CVE-2021-20091

CVE-2021-20091 is a high-severity vulnerability in Buffalo Wsr-2533dhpl2-bk Firmware with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.5
EPSS exploit prediction: 9% (94th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Buffalo Wsr-2533dhpl2-bk Firmware
Published: 2021-04-29
Last modified: 2026-06-17

Description

The web interfaces of Buffalo WSR-2533DHPL2 firmware version <= 1.02 and WSR-2533DHP3 firmware version <= 1.24 do not properly sanitize user input. An authenticated remote attacker could leverage this vulnerability to alter device configuration, potentially gaining remote code execution.

Frequently asked questions

What is CVE-2021-20091?: The web interfaces of Buffalo WSR-2533DHPL2 firmware version <= 1.02 and WSR-2533DHP3 firmware version <= 1.24 do not properly sanitize user input. An authenticated remote attacker could leverage this vulnerability to alter device configuration, potentially gaining remote code execution.
How severe is CVE-2021-20091?: CVE-2021-20091 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-20091 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (94th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20091?: CVE-2021-20091 primarily affects Buffalo Wsr-2533dhpl2-bk Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20091?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-20091 published?: CVE-2021-20091 was published on 2021-04-29 and last updated on 2026-06-17.

References

https://www.tenable.com/security/research/tra-2021-13

Affected products (2)

cpe:2.3:o:buffalo:wsr-2533dhpl2-bk_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:buffalo:wsr-2533dhp3-bk_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Buffalo Wsr-2533dhpl2-bk Firmware

CVE-2021-20090 — Critical (CVSS 9.8): A path traversal vulnerability in the web interfaces of Buffalo WSR-2533DHPL2 firmware version <= 1.02 and WSR-2533DHP3…
CVE-2021-20092 — High (CVSS 7.5): The web interfaces of Buffalo WSR-2533DHPL2 firmware version <= 1.02 and WSR-2533DHP3 firmware version <= 1.24 do not…

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