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Fencer Vulns
medium 5.4

CVE-2020-12256 json

rConfig 3.9.4 is vulnerable to reflected XSS.

published 2020-05-18 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-4570

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
95.9%
EPSS 95.9% chance of exploitation in 30 days, percentile 99.8%
public exploits
0
none known, plus a Nuclei check

Summary

rConfig 3.9.4 is vulnerable to reflected XSS. The devicemgmnt.php file improperly validates user input. An attacker can exploit this by crafting arbitrary JavaScript in the deviceId GET parameter to devicemgmnt.php.

Exploit prediction

95.94% chance of exploitation in the next 30 days, higher than 99.8% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template rConfig 3.9.4 - Cross-Site Scripting nuclei detection template
  • gist.github.com https://gist.github.com/farid007/8855031bad0e497264e4879efb5bc9f8 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N

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.