CVE-2020-26227: Typo3/cms core Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-vqqx-jw6p-q3rf
CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2020-26227 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Typo3/cms core libraries in the Packagist ecosystem. The issue involves cross-site scripting in fluid view helpers. Remediation is available by upgrading affected packages to version 9.5.23, 10.4.10, 8.7.38.

CVE-2020-26227 at a Glance

CVE Identifier CVE-2020-26227
GHSA Identifier GHSA-vqqx-jw6p-q3rf
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Typo3/cms core
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 6.1

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

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

How to Fix CVE-2020-26227

To remediate this vulnerability, upgrade all affected Typo3/cms core dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

typo3/cms-core fixed: 9.5.23
Upgrade typo3/cms-core to 9.5.23
typo3/cms-core fixed: 10.4.10
Upgrade typo3/cms-core to 10.4.10
typo3/cms-core fixed: 8.7.38
Upgrade typo3/cms-core to 8.7.38
typo3/cms fixed: 10.4.10
Upgrade typo3/cms to 10.4.10
typo3/cms fixed: 9.5.23
Upgrade typo3/cms to 9.5.23
typo3/cms fixed: 8.7.38
Upgrade typo3/cms to 8.7.38
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 typo3/cms-core

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-26227, inspect your project dependencies for Typo3/cms core:

inspect dependencies for typo3/cms-core

Analyze the terminal output to locate any version of Typo3/cms core in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 9.5.23), 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 Typo3/cms core, 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

> ### Meta > * CVSS: `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C` (5.7) > * CWE-79 ### Problem It has been discovered that system extension Fluid (`typo3/cms-fluid`) of the TYPO3 core is vulnerable to cross-site scripting passing user-controlled data as argument to Fluid view helpers. ``` <f:form ... fieldNamePrefix="{payload}" /> <f:be.labels.csh ... label="{payload}" /> <f:be.menus.actionMenu ... label="{payload}" /> ``` ### Solution Update to TYPO3 versions 9.5.23 or 10.4.10 that fix the problem described. ### Credits Thanks to TYPO3 security team member Oliver Hader who reported this issue and to TYPO3 security team members Helmut Hummel & Oliver Hader who fixed the issue. ### References * [TYPO3-CORE-SA-2020-010](https://typo3.org/security/advisory/typo3-core-sa-2020-010)

CVE-2020-26227 Affected Typo3/cms core Versions

6 component(s)
Fixed Versions:
9.5.2310.4.108.7.38
Product / Package Ecosystem Affected Versions Fixed Version
typo3/cms-core
Packagist
≥ 9.0.0
< 9.5.23
9.5.23
typo3/cms-core
Packagist
≥ 10.0.0
< 10.4.10
10.4.10
typo3/cms-core
Packagist
≥ 8.7.0
< 8.7.38
8.7.38
typo3/cms
Packagist
≥ 10.0.0
< 10.4.10
10.4.10
typo3/cms
Packagist
≥ 9.0.0
< 9.5.23
9.5.23
typo3/cms
Packagist
≥ 8.7.0
< 8.7.38
8.7.38

References

Frequently Asked Questions

What is CVE-2020-26227?
CVE-2020-26227 is a security vulnerability in Typo3/cms core involving Cross-Site Scripting in Fluid view helpers under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Typo3/cms core versions are affected?
Affected versions include releases prior to 9.5.23, 10.4.10, 8.7.38 across affected packages: typo3/cms-core, typo3/cms.
What version fixes CVE-2020-26227?
Upgrading to 9.5.23, 10.4.10, 8.7.38 (or the latest patched release for your respective branch) resolves the vulnerability.
Is typo3/cms-core affected?
Yes, typo3/cms-core is affected in releases prior to 9.5.23, 10.4.10, 8.7.38. Upgrade your dependency to 9.5.23, 10.4.10, 8.7.38 or later.
Is typo3/cms affected?
Yes, typo3/cms is affected in releases prior to 10.4.10, 9.5.23, 8.7.38. Upgrade your dependency to 10.4.10, 9.5.23, 8.7.38 or later.
What is the CVSS score of CVE-2020-26227?
CVE-2020-26227 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2020-26227?
CVE-2020-26227 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-2020-26227?
Run the dependency tree command: 'inspect dependencies for typo3/cms-core'. 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-vqqx-jw6p-q3rf",
  "modified" : "2021-01-07T22:34:28Z",
  "published" : "2020-12-21T16:28:11Z",
  "aliases" : [ "CVE-2020-26227" ],
  "summary" : "Cross-Site Scripting in Fluid view helpers",
  "details" : "> ### Meta\n> * CVSS: `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C` (5.7)\n> * CWE-79\n\n### Problem\nIt has been discovered that system extension Fluid (`typo3/cms-fluid`) of the TYPO3 core is vulnerable to cross-site scripting passing user-controlled data as argument to Fluid view helpers.\n\n```\n<f:form ... fieldNamePrefix=\"{payload}\" />\n<f:be.labels.csh ... label=\"{payload}\" />\n<f:be.menus.actionMenu ... label=\"{payload}\" />\n```\n\n### Solution\nUpdate to TYPO3 versions 9.5.23 or 10.4.10 that fix the problem described.\n\n### Credits\nThanks to TYPO3 security team member Oliver Hader who reported this issue and to TYPO3 security team members Helmut Hummel & Oliver Hader who fixed the issue.\n\n### References\n* [TYPO3-CORE-SA-2020-010](https://typo3.org/security/advisory/typo3-core-sa-2020-010)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.5.23"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0"
      }, {
        "fixed" : "10.4.10"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.7.0"
      }, {
        "fixed" : "8.7.38"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0"
      }, {
        "fixed" : "10.4.10"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.5.23"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.7.0"
      }, {
        "fixed" : "8.7.38"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-vqqx-jw6p-q3rf"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-26227"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2020-26227.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2020-26227.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://packagist.org/packages/typo3/cms-core"
  }, {
    "type" : "WEB",
    "url" : "https://typo3.org/security/advisory/typo3-core-sa-2020-010"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-12-21T16:11:44Z",
    "nvd_published_at" : null
  }
}