CVE-2026-30877: Baserproject/basercms BaserCMS Update Functionality Vulnerable To Vulnerability

CRITICAL
Advisory Identifier: GHSA-m9g7-rgfc-jcm7
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CVSS 9.1
CWE-78
Published
Advisory Summary

CVE-2026-30877 is a CRITICAL (CVSS 9.1) basercms update functionality vulnerable to vulnerability (CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')) affecting Baserproject/basercms libraries in the Packagist ecosystem. The issue involves basercms update functionality vulnerable to os command injection. Remediation is available by upgrading affected packages to version 5.2.3.

CVE-2026-30877 at a Glance

CVE Identifier CVE-2026-30877
GHSA Identifier GHSA-m9g7-rgfc-jcm7
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Affected Product Baserproject/basercms
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required High (PR:H)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-30877

To remediate this vulnerability, upgrade all affected Baserproject/basercms dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

baserproject/basercms fixed: 5.2.3 
Upgrade baserproject/basercms to 5.2.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for baserproject/basercms

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-30877, inspect your project dependencies for Baserproject/basercms:

inspect dependencies for baserproject/basercms

Analyze the terminal output to locate any version of Baserproject/basercms in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.2.3), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'), where the product constructs all or part of an os command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended os command when it is sent to a downstream component. In Baserproject/basercms, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary The latest version of baserCMS (basercms-5.2.2) contains an OS command injection vulnerability (CWE-78) in its 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. ### Details Please refer to the attached materials. [OSコマンドインジェクション（baserCMSのアップデート機能）.pdf](https://github.com/user-attachments/files/25468689/OS.baserCMS.pdf) ### Impact An authenticated user with administrator privileges in baserCMS can execute OS commands on the server with the privileges of the user account running baserCMS.

CVE-2026-30877 Affected Baserproject/basercms Versions

1 component(s)
Fixed Versions:
5.2.3
Product / Package Ecosystem Affected Versions Fixed Version
baserproject/basercms
 Packagist
< 5.2.3
5.2.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/baserproject/basercms/security/advisories/GHSA-m9g7-rgfc-jcm7
NVD — CVE-2026-30877 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-30877
Baserproject/basercms Security Information SECURITY
https://basercms.net/security/JVN_20837860
Baserproject/basercms Source Repository REPOSITORY
https://github.com/baserproject/basercms
Baserproject/basercms Release RELEASE
https://github.com/baserproject/basercms/releases/tag/5.2.3

Frequently Asked Questions

What is CVE-2026-30877?
CVE-2026-30877 is a security vulnerability in Baserproject/basercms involving baserCMS Update Functionality Vulnerable to OS Command Injection under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection').
Which Baserproject/basercms versions are affected?
Affected versions include releases prior to 5.2.3 across affected packages: baserproject/basercms.
What version fixes CVE-2026-30877?
Upgrading to 5.2.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is baserproject/basercms affected?
Yes, baserproject/basercms is affected in releases prior to 5.2.3. Upgrade your dependency to 5.2.3 or later.
What is the CVSS score of CVE-2026-30877?
CVE-2026-30877 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2026-30877?
CVE-2026-30877 is classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') (The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.).
How can I check Packagist dependencies for CVE-2026-30877?
Run the dependency tree command: 'inspect dependencies for baserproject/basercms'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-m9g7-rgfc-jcm7",
  "modified" : "2026-03-31T22:35:47Z",
  "published" : "2026-03-31T22:35:47Z",
  "aliases" : [ "CVE-2026-30877" ],
  "summary" : "baserCMS Update Functionality Vulnerable to OS Command Injection",
  "details" : "### Summary\nThe latest version of baserCMS (basercms-5.2.2) contains an OS command injection vulnerability (CWE-78) in its update functionality.\nDue 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.\n\n### Details\nPlease refer to the attached materials.\n[OSコマンドインジェクション（baserCMSのアップデート機能）.pdf](https://github.com/user-attachments/files/25468689/OS.baserCMS.pdf)\n\n\n\n### Impact\nAn authenticated user with administrator privileges in baserCMS can execute OS commands on the server with the privileges of the user account running baserCMS.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "baserproject/basercms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.2.3"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 5.2.2"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/baserproject/basercms/security/advisories/GHSA-m9g7-rgfc-jcm7"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-30877"
  }, {
    "type" : "WEB",
    "url" : "https://basercms.net/security/JVN_20837860"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/baserproject/basercms"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/baserproject/basercms/releases/tag/5.2.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-78" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-31T22:35:47Z",
    "nvd_published_at" : "2026-03-31T01:16:35Z"
  }
}