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Fencer Intel
critical 9.1

CVE-2021-41243 json

OS Command Injection Vulnerability and Potential Zip Slip Vulnerability

published 4y ago modified last mo. also GHSA-7rpc-9m88-cf9w , EUVD-2021-2476

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

There is a Potential Zip Slip Vulnerability and OS Command Injection Vulnerability on the management system of baserCMS. Users with permissions to upload files may upload crafted zip files which may execute arbitrary commands on the host operating system. This is a vulnerability that needs to be addressed when the management system is used by an unspecified number of users. If you are eligible, please update to the new version as soon as possible.

Patch / fix

  • packagist baserproject/basercms 4.5.4
  • basercms basercms 4.5.4

Is CVE-2021-41243 in your dependencies? 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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Exploit prediction

2.17% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C
GitHub 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L

Affected packages

ecosystem package affected fixed in
packagist baserproject/basercms
<4.5.4
4.5.4

Affected products

  • baserproject basercms

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

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.