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No exploitation reportedFix available

CVE-2021-41243

No exploitation reported by the sources we read.

  • Published2021-11-26
  • Fixed in4.5.4
  • WeaknessCWE-78

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2021-11-2618:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-41243?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-41243?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Basercms
BranchAffectedFixed in
4.5< 4.5.44.5.4

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Basercms to 4.5.4

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CNACVSS 3.19.1read 2026-10-23
  • NVDCVSS 3.18.8read 2026-10-23
  • NVDCVSS 2.09read 2026-10-23
  • CNAweakness (CWE)CWE-78read 2026-10-23
  • FIRST EPSSEPSS score2.2 %2026-10-22
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2021-11-26
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-41243?

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.

Is CVE-2021-41243 actively exploited?

Active exploitation of CVE-2021-41243 has not been confirmed. Its EPSS score was 2.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-41243?

CVE-2021-41243 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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