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Fencer Intel
medium 5.3

CVE-2021-47860 json

GetSimple CMS Custom JS 0.1 - CSRF to XSS to RCE

published 9mo ago modified 4mo ago also EUVD-2026-3611

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

GetSimple CMS Custom JS 0.1 plugin contains a cross-site request forgery vulnerability that allows unauthenticated attackers to inject arbitrary client-side code into administrator browsers. Attackers can craft a malicious website that triggers a cross-site scripting payload to execute remote code on the hosting server when an authenticated administrator visits the page.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
9mo ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • exploit-db.com https://www.exploit-db.com/exploits/49816 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/boku7/gsCMS-CustomJS-Csrf2Xss2Rce referenced PoC, tagged "exploit" by a source, unverified
  • exploit-db.com https://www.exploit-db.com/exploits/49712 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CNA 4.0 8.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Affected products

  • GetSimple CMS Custom JS Plugin

Classification

Weakness
  • CWE-352 Cross-Site Request Forgery

References

Sources

Fencer Intel 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.