CVE-2023-36806: Contao/core bundle Cross Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-4gpr-p634-922x
CVSS 6.6
CWE-79
Published
Advisory Summary

CVE-2023-36806 is a MODERATE (CVSS 6.6) cross site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Contao/core bundle libraries in the Packagist ecosystem. The issue involves cross site scripting via input unit widget. Remediation is available by upgrading affected packages to version 4.9.42, 4.13.28, 5.1.10.

CVE-2023-36806 at a Glance

CVE Identifier CVE-2023-36806
GHSA Identifier GHSA-4gpr-p634-922x
Severity MODERATE
CVSS v3.1 Base Score 6.6
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Contao/core bundle
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 6.6

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:L/I:L/A:L).

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 Low (C:L)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2023-36806

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

contao/core-bundle fixed: 4.9.42
Upgrade contao/core-bundle to 4.9.42
contao/core-bundle fixed: 4.13.28
Upgrade contao/core-bundle to 4.13.28
contao/core-bundle fixed: 5.1.10
Upgrade contao/core-bundle to 5.1.10
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 contao/core-bundle

How to Check if You Are Affected

To determine whether your application is affected by CVE-2023-36806, inspect your project dependencies for Contao/core bundle:

inspect dependencies for contao/core-bundle

Analyze the terminal output to locate any version of Contao/core bundle in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.9.42), 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 Contao/core bundle, 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

### Impact Authenticated users can inject malicious code in widgets with units, which is then executed both in the element preview (back end) and on the website (front end). ### Patches Update to Contao 4.9.42, 4.13.28 or 5.1.10. ### Workarounds Disable login for all untrusted back end users. ### References https://contao.org/en/security-advisories/cross-site-scripting-in-widgets-with-units ### For more information If you have any questions or comments about this advisory, open an issue in [contao/contao](https://github.com/contao/contao/issues/new/choose). ### Credits Thanks to Christian Pöschl and Fabian Brenner from usd AG for reporting this vulnerability.

CVE-2023-36806 Affected Contao/core bundle Versions

3 component(s)
Fixed Versions:
4.9.424.13.285.1.10
Product / Package Ecosystem Affected Versions Fixed Version
contao/core-bundle
Packagist
≥ 4.0.0
< 4.9.42
4.9.42
contao/core-bundle
Packagist
≥ 4.10.0
< 4.13.28
4.13.28
contao/core-bundle
Packagist
≥ 5.0.0
< 5.1.10
5.1.10

References

Frequently Asked Questions

What is CVE-2023-36806?
CVE-2023-36806 is a security vulnerability in Contao/core bundle involving Cross site scripting via input unit widget under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Contao/core bundle versions are affected?
Affected versions include releases prior to 4.9.42, 4.13.28, 5.1.10 across affected packages: contao/core-bundle.
What version fixes CVE-2023-36806?
Upgrading to 4.9.42, 4.13.28, 5.1.10 (or the latest patched release for your respective branch) resolves the vulnerability.
Is contao/core-bundle affected?
Yes, contao/core-bundle is affected in releases prior to 4.9.42, 4.13.28, 5.1.10. Upgrade your dependency to 4.9.42, 4.13.28, 5.1.10 or later.
What is the CVSS score of CVE-2023-36806?
CVE-2023-36806 has a CVSS v3.1 base score of 6.6 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L.
What CWE is associated with CVE-2023-36806?
CVE-2023-36806 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-2023-36806?
Run the dependency tree command: 'inspect dependencies for contao/core-bundle'. 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
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4gpr-p634-922x",
  "modified" : "2025-04-17T12:44:36Z",
  "published" : "2023-07-25T17:19:10Z",
  "aliases" : [ "CVE-2023-36806" ],
  "summary" : "Cross site scripting via input unit widget",
  "details" : "### Impact\n\nAuthenticated users can inject malicious code in widgets with units, which is then executed both in the element preview (back end) and on the website (front end).\n\n### Patches\n\nUpdate to Contao 4.9.42, 4.13.28 or 5.1.10.\n\n### Workarounds\n\nDisable login for all untrusted back end users.\n\n### References\n\nhttps://contao.org/en/security-advisories/cross-site-scripting-in-widgets-with-units\n\n### For more information\n\nIf you have any questions or comments about this advisory, open an issue in [contao/contao](https://github.com/contao/contao/issues/new/choose).\n\n### Credits\n\nThanks to Christian Pöschl and Fabian Brenner from usd AG for reporting this vulnerability.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "contao/core-bundle"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.9.42"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "contao/core-bundle"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.10.0"
      }, {
        "fixed" : "4.13.28"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "contao/core-bundle"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.0.0"
      }, {
        "fixed" : "5.1.10"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/contao/contao/security/advisories/GHSA-4gpr-p634-922x"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-36806"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/contao/contao/commit/5c9aff32cfc1f7dc452a045862ac2f86a6b9b4b4"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/contao/contao/commit/c98585d36baa25fda69c062421e7e7eadc53c82b"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/contao/contao/commit/ccb64c777eb0f9c0e6490c9135d80e915d37cd32"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/contao/contao"
  }, {
    "type" : "WEB",
    "url" : "https://herolab.usd.de/security-advisories/usd-2023-0020"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-07-25T17:19:10Z",
    "nvd_published_at" : "2023-07-25T19:15:11Z"
  }
}