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Fencer Intel
high 7.3

CVE-2026-3395 json

MaxSite CMS MarkItUp Preview AJAX Endpoint preview-ajax.php eval code injection

published 8mo ago modified 4mo ago also EUVD-2026-9130

cvss
7.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
4.0%
EPSS 4.0% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known, plus a Nuclei check

Summary

A flaw has been found in MaxSite CMS up to 109.1. This impacts the function eval of the file application/maxsite/admin/plugins/editor_markitup/preview-ajax.php of the component MarkItUp Preview AJAX Endpoint. Executing a manipulation can lead to code injection. It is possible to launch the attack remotely. The exploit has been published and may be used. Upgrading to version 109.2 will fix this issue. This patch is called 08937a3c5d672a242d68f53e9fccf8a748820ef3. You should upgrade the affected component. The code maintainer was informed beforehand about the issues. He reacted very fast and highly professional.

Patch / fix

  • MaxSite CMS 109.2

Is CVE-2026-3395 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
8mo ago

Exploit prediction

4.02% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • Nuclei template MaxSite CMS <=109.1 - Remote Code Execution nuclei detection template

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C
CNA 3.0 7.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C
CNA 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P/E:POC/RL:OF/RC:C
CNA 4.0 5.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • MaxSite CMS

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

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.