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Fencer Intel
critical 9.1

CVE-2026-56660 json

GetSimple CMS: CSRF, SSRF, and Unrestricted Zip Extraction

published 4mo ago modified last mo. also EUVD-2026-91016 , GHSA-q5rx-gppg-768r

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository GetSimpleCMS-CE/GetSimpleCMS-CE. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

GetSimple CMS is a content management system (CMS), and GetSimple CMS CE is the community edition of that CMS. Prior to version 1.5, the update handler in UpdateCE.php downloads a ZIP archive and extracts its contents into the web root without validating file types or extraction paths. Because PHP files are written into a web-accessible directory, an attacker who can cause a malicious archive to be processed achieves remote code execution as the web-server user. Entry names are also used unsafely, allowing directory traversal (../) to write files outside the intended extraction directory. This issue has been patched in version 1.5.

Patch / fix

  • getsimple-ce getsimple_cms 1.5

Is CVE-2026-56660 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
no
Technical impact
total
Assessed
last mo.

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/GetSimpleCMS-CE/GetSimpleCMS-CE/security/advisories/GHSA-q5rx-gppg-768r referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Affected products

  • GetSimpleCMS-CE GetSimpleCMS-CE

Classification

Weakness
  • CWE-352 Cross-Site Request Forgery
  • CWE-434 Unrestricted Upload of File with Dangerous Type
  • CWE-918 Server-Side 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.

The maintainers of GetSimpleCMS-CE/GetSimpleCMS-CE published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.