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Fencer Intel
high 7.2

CVE-2021-28976 json

Remote Code Execution vulnerability in GetSimpleCMS before 3.3.16 in admin/upload.php via phar filess.

published 5y ago modified 4mo ago also EUVD-2021-15623

cvss
7.2
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
7.5%
EPSS 7.5% chance of exploitation in 30 days, percentile 94%
public exploits
1
Exploit-DB

Summary

Remote Code Execution vulnerability in GetSimpleCMS before 3.3.16 in admin/upload.php via phar filess.

Patch / fix

  • get-simple getsimplecms 3.3.15

Is CVE-2021-28976 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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Timeline

  1. Published
  2. First public exploit (EDB-52168)

Exploit prediction

7.55% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-52168 GetSimpleCMS 3.3.16 - Remote Code Execution (RCE) webapps, 2025-04-11

CVSS scores

assigned by version score vector
NVD 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type

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.