---
title: "CVE-2026-30877: baserCMS Update Functionality Vulnerable to OS Command Injection"
url: https://erroneo.us/security/cve/CVE-2026-30877/
description: "CVE-2026-30877 (baserproject/basercms (Composer (PHP))): baserCMS is a website development framework. Prior to version 5.2.3, there is an OS command…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-31
date_modified: 2026-04-02
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-30877"
kev: false
cvss: 9.1
epss: 0.02058
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-30877: baserCMS Update Functionality Vulnerable to OS Command Injection

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 2.1% , percentile 81: FIRST’s model estimates a 2.1% chance of exploitation activity in the next 30 days, higher than 81% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Needs an account (high (admin)). Exposure depends on who can log in.
- Only applies if your dependency tree includes baserproject/basercms (Composer (PHP)) <= 5.2.2, fixed in 5.2.3 . Check your lockfile, including transitive dependencies.

## What it is

baserCMS is a website development framework. Prior to version 5.2.3, there is an OS command injection vulnerability in the update functionality. Due to this issue, an authenticated user with administrator privileges in baserCMS can execute arbitrary OS commands on the server with the privileges of the user account running baserCMS. This issue has been patched in version 5.2.3.

## Affected packages

- Composer (PHP) `baserproject/basercms` <= 5.2.2 → fixed: 5.2.3

## Affected products (CVE record)

- baserproject basercms: < 5.2.3

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 2.06% probability of exploitation activity in the next 30 days; percentile 81.

## Sources

- [GitHub Advisory GHSA-m9g7-rgfc-jcm7](https://github.com/advisories/GHSA-m9g7-rgfc-jcm7)
- [CVE.org record CVE-2026-30877](https://www.cve.org/CVERecord?id=CVE-2026-30877)
- [NVD entry CVE-2026-30877](https://nvd.nist.gov/vuln/detail/CVE-2026-30877)
- [github.com](https://github.com/baserproject/basercms/security/advisories/GHSA-m9g7-rgfc-jcm7)
- [basercms.net](https://basercms.net/security/JVN_20837860)
- [github.com](https://github.com/baserproject/basercms/releases/tag/5.2.3)

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Source page: https://erroneo.us/security/cve/CVE-2026-30877/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt