CVE-2026-30879: Baserproject/basercms Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-jmq3-x8q7-j9qm
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CWE-79
Published
Advisory Summary

CVE-2026-30879 is a MODERATE cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Baserproject/basercms libraries in the Packagist ecosystem. The issue involves basercms has a cross-site scripting vulnerability in blog posts. Remediation is available by upgrading affected packages to version 5.2.3.

CVE-2026-30879 at a Glance

CVE Identifier CVE-2026-30879
GHSA Identifier GHSA-jmq3-x8q7-j9qm
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Baserproject/basercms
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-30879

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-2026-30879, 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-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. 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

baserCMS has a cross-site scripting vulnerability in blog posts. ### Target baserCMS 5.2.1 and earlier versions ### Vulnerability Malicious Javascript may be executed in blog posts. ### Countermeasures Update to the latest version of baserCMS Please refer to the following page to reference for more information. https://basercms.net/security/JVN_20837860 ### Credits Gai Tanaka@Mitsui Bussan Secure Directions, Inc.

CVE-2026-30879 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-jmq3-x8q7-j9qm
NVD — CVE-2026-30879 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-30879
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-2026-30879?
CVE-2026-30879 is a security vulnerability in Baserproject/basercms involving baserCMS has a cross-site scripting vulnerability in blog posts under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Baserproject/basercms versions are affected?
Affected versions include releases prior to 5.2.3 across affected packages: baserproject/basercms.
What version fixes CVE-2026-30879?
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 CWE is associated with CVE-2026-30879?
CVE-2026-30879 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Packagist dependencies for CVE-2026-30879?
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-jmq3-x8q7-j9qm",
  "modified" : "2026-03-31T22:43:10Z",
  "published" : "2026-03-31T22:43:10Z",
  "aliases" : [ "CVE-2026-30879" ],
  "summary" : "baserCMS has a cross-site scripting vulnerability in blog posts",
  "details" : "baserCMS has a cross-site scripting vulnerability in blog posts.\n\n### Target\nbaserCMS 5.2.1 and earlier versions\n\n### Vulnerability\n\nMalicious Javascript may be executed in blog posts.\n\n### Countermeasures\nUpdate to the latest version of baserCMS\n\nPlease refer to the following page to reference for more information.\nhttps://basercms.net/security/JVN_20837860\n\n### Credits\n\nGai Tanaka@Mitsui Bussan Secure Directions, Inc.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N"
  } ],
  "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-jmq3-x8q7-j9qm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-30879"
  }, {
    "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-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-31T22:43:10Z",
    "nvd_published_at" : "2026-03-31T01:16:36Z"
  }
}