CVE-2025-8571: Concrete5/concrete5 Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-4pcg-pjp5-3mc6
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CWE-20 CWE-79
Published
Advisory Summary

CVE-2025-8571 is a MODERATE cross-site scripting vulnerability (CWE-20: Improper Input Validation) affecting Concrete5/concrete5 libraries in the Packagist ecosystem. The issue involves concrete cms vulnerable to reflected cross-site scripting (xss) in conversation messages dashboard page. Remediation is available by upgrading affected packages to version 8.5.21, 9.4.3.

CVE-2025-8571 at a Glance

CVE Identifier CVE-2025-8571
GHSA Identifier GHSA-4pcg-pjp5-3mc6
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-20: Improper Input Validation
Affected Product Concrete5/concrete5
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2025-8571

To remediate this vulnerability, upgrade all affected Concrete5/concrete5 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

concrete5/concrete5 fixed: 8.5.21 
Upgrade concrete5/concrete5 to 8.5.21
concrete5/concrete5 fixed: 9.4.3 
Upgrade concrete5/concrete5 to 9.4.3
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 concrete5/concrete5

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-8571, inspect your project dependencies for Concrete5/concrete5:

inspect dependencies for concrete5/concrete5

Analyze the terminal output to locate any version of Concrete5/concrete5 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 8.5.21), 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-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In Concrete5/concrete5, 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

Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions.

CVE-2025-8571 Affected Concrete5/concrete5 Versions

2 component(s)
Fixed Versions:
8.5.219.4.3
Product / Package Ecosystem Affected Versions Fixed Version
concrete5/concrete5
 Packagist
< 8.5.21
8.5.21
concrete5/concrete5
 Packagist
≥ 9.0.0RC1
< 9.4.3
9.4.3

References

documentation.concretecms.org/developers/introduc... WEB
https://documentation.concretecms.org/developers/introduction/version-history/8521-release-notes
Concrete5/concrete5 Source Repository REPOSITORY
https://github.com/concretecms/concretecms
NVD — CVE-2025-8571 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-8571
www.concretecms.org/download WEB
https://www.concretecms.org/download
Security Fix Commit FIX COMMIT
https://github.com/concretecms/concretecms/commit/4b39dcc17c309dc82eb8398e8cdb146942f62f92
Security Fix Commit FIX COMMIT
https://github.com/concretecms/concretecms/commit/f7630b467d3a234d3d333ca117046a500e7ee2b6
documentation.concretecms.org/9-x/developers/intr... WEB
https://documentation.concretecms.org/9-x/developers/introduction/version-history/943-release-notes

Frequently Asked Questions

What is CVE-2025-8571?
CVE-2025-8571 is a security vulnerability in Concrete5/concrete5 involving Concrete CMS vulnerable to Reflected Cross-Site Scripting (XSS) in Conversation Messages Dashboard Page under CWE-20: Improper Input Validation.
Which Concrete5/concrete5 versions are affected?
Affected versions include releases prior to 8.5.21, 9.4.3 across affected packages: concrete5/concrete5.
What version fixes CVE-2025-8571?
Upgrading to 8.5.21, 9.4.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is concrete5/concrete5 affected?
Yes, concrete5/concrete5 is affected in releases prior to 8.5.21, 9.4.3. Upgrade your dependency to 8.5.21, 9.4.3 or later.
What CWE is associated with CVE-2025-8571?
CVE-2025-8571 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check Packagist dependencies for CVE-2025-8571?
Run the dependency tree command: 'inspect dependencies for concrete5/concrete5'. 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-4pcg-pjp5-3mc6",
  "modified" : "2025-08-06T17:24:47Z",
  "published" : "2025-08-06T00:30:25Z",
  "aliases" : [ "CVE-2025-8571" ],
  "summary" : "Concrete CMS vulnerable to Reflected Cross-Site Scripting (XSS) in Conversation Messages Dashboard Page",
  "details" : "Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "concrete5/concrete5"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "8.5.21"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "concrete5/concrete5"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0RC1"
      }, {
        "fixed" : "9.4.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-8571"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/concretecms/concretecms/commit/4b39dcc17c309dc82eb8398e8cdb146942f62f92"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/concretecms/concretecms/commit/f7630b467d3a234d3d333ca117046a500e7ee2b6"
  }, {
    "type" : "WEB",
    "url" : "https://documentation.concretecms.org/9-x/developers/introduction/version-history/943-release-notes"
  }, {
    "type" : "WEB",
    "url" : "https://documentation.concretecms.org/developers/introduction/version-history/8521-release-notes"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/concretecms/concretecms"
  }, {
    "type" : "WEB",
    "url" : "https://www.concretecms.org/download"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20", "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-08-06T17:24:47Z",
    "nvd_published_at" : "2025-08-05T23:15:38Z"
  }
}