How severe is CVE-2021-20137?

CVE-2021-20137 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-20137 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20137?

CVE-2021-20137 affects Gryphonconnect Gryphon Tower Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-20137?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-20137 published?

CVE-2021-20137 was published on 2021-12-09 and last updated on 2026-06-17.

CVE-2021-20137

CVE-2021-20137 is a medium-severity vulnerability in Gryphonconnect Gryphon Tower Firmware with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 3% (83rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Gryphonconnect Gryphon Tower Firmware
Published: 2021-12-09
Last modified: 2026-06-17

Description

A reflected cross-site scripting vulnerability exists in the url parameter of the /cgi-bin/luci/site_access/ page on the Gryphon Tower router's web interface. An attacker could exploit this issue by tricking a user into following a specially crafted link, granting the attacker javascript execution in the context of the victim's browser.

Frequently asked questions

What is CVE-2021-20137?: A reflected cross-site scripting vulnerability exists in the url parameter of the /cgi-bin/luci/site_access/ page on the Gryphon Tower router's web interface. An attacker could exploit this issue by tricking a user into following a specially crafted link, granting the attacker javascript execution in the context of the victim's browser.
How severe is CVE-2021-20137?: CVE-2021-20137 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-20137 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20137?: CVE-2021-20137 affects Gryphonconnect Gryphon Tower Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20137?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-20137 published?: CVE-2021-20137 was published on 2021-12-09 and last updated on 2026-06-17.

References

https://www.tenable.com/security/research/tra-2021-51

Affected products (1)

cpe:2.3:o:gryphonconnect:gryphon_tower_firmware:*:*:*:*:*:*:*:*

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