CVE-2026-21861 json
baserCMS: OS Command Injection Leading to Remote Code Execution (RCE)
published 2026-03-31 7 mo ago modified 2026-09-10 1 mo ago also EUVD-2026-17255 , GHSA-qxmc-6f24-g86g
- cvss
- 9.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 2.3%
- EPSS 2.3% chance of exploitation in 30 days, percentile 83%
- public exploits
- 0
- none known
Summary
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 due to improper handling of user-controlled input that is directly passed to exec() without sufficient validation or escaping. This issue has been patched in version 5.2.3.
Patch / fix
- packagist baserproject/basercms 5.2.3
- basercms basercms 5.2.3
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 7 mo ago
Exploit prediction
2.32% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/baserproject/basercms/security/advisories/GHSA-qxmc-6f24-g86g 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 |
| GitHub | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H |
| NVD | 3.1 | 7.2 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | baserproject/basercms | <5.2.3 |
5.2.3 |
Affected products
- baserproject basercms
Classification
- Weakness
-
- CWE-78 Improper Neutralization of Special Elements used in an OS Command
References
-
github.com
/baserproject/basercms/security/advisories/GHSA-qxmc-6f24-g86g
exploit, web, vendor-advisory
-
basercms.net
/security/JVN_20837860
web, vendor-advisory
-
github.com
/baserproject/basercms/releases/tag/5.2.3
web, release-notes
-
nvd.nist.gov
/vuln/detail/CVE-2026-21861
advisory
-
github.com
/baserproject/basercms
package
Sources
- CVE List CVE-2026-21861
- GitHub Advisory GHSA-qxmc-6f24-g86g
- NVD CVE-2026-21861
Fencer Vulns 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.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.