What is CVE-2026-21861?

CVE-2026-21861 is a critical-severity vulnerability in Baserproject Basercms, classified under OS Command Injection. CVSS score: 9.1/10. Published 2026-03-31.

How severe is CVE-2026-21861?

Critical severity. CVSS v3 base score is 9.1 out of 10.

RCE in Baserproject Basercms

CVE-2026-21861

baserCMS is a website development framework. Prior to version 5.2.3, baserCMS contains an OS command injection vulnerability in the core update functionality. An authenticated administrator can execute arbitrary OS commands on the server d…

Vulnerability class: Command Injection (OS Command Injection)

EPSS: 0.001 (32.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.

Affected products

Baserproject Basercms — versions < 5.2.3

Weakness classification (CWE)

CWE-78 — OS Command Injection

References

https://github.com/baserproject/basercms/security/advisories/GHSA-qxmc-6f24-g86g (x_refsource_CONFIRM)
https://basercms.net/security/JVN_20837860 (x_refsource_MISC)
https://github.com/baserproject/basercms/releases/tag/5.2.3 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-21861?: CVE-2026-21861 is a critical-severity vulnerability in Baserproject Basercms, classified under OS Command Injection. CVSS score: 9.1/10. Published 2026-03-31.
How severe is CVE-2026-21861?: Critical severity. CVSS v3 base score is 9.1 out of 10.