GetSimple CMS Custom JS 0.1 - CSRF to XSS to RCE

published 2026-01-21 9 mo ago modified 2026-06-17 4 mo 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

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.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: partial
Assessed: 9 mo ago (2026-01-22)

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

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

exploit-db.com /exploits/49816
exploit, third-party-advisory, vdb-entry
github.com /boku7/gsCMS-CustomJS-Csrf2Xss2Rce
technical-description, exploit, third-party-advisory
exploit-db.com /exploits/49712
exploit, third-party-advisory, vdb-entry
get-simple.info
product
github.com /GetSimpleCMS/GetSimpleCMS
product
vulncheck.com /advisories/getsimple-cms-custom-js-csrf-to-xss-to-rce
third-party-advisory

Sources

CVE List CVE-2021-47860
NVD CVE-2021-47860

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.

Summary