Skip to content
Fencer Vulns
medium 6.1

CVE-2021-20137 json

A reflected cross-site scripting vulnerability exists in the url parameter of the /cgi-bin/luci/site_access/ page on the Gryphon Tower rout…

published 2021-12-09 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-7594

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known, plus a Nuclei check

Summary

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.

Exploit prediction

2.31% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template Gryphon Tower - Cross-Site Scripting nuclei detection template
  • tenable.com https://www.tenable.com/security/research/tra-2021-51 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

  • n/a Gryphon Tower router

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.