CVE-2020-26229: Typo3/cms core XML External Entity Vulnerability

LOW
Advisory Identifier: GHSA-q9cp-mc96-m4w2
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CVSS 3.7
CWE-611
Published
Advisory Summary

CVE-2020-26229 is a LOW (CVSS 3.7) xml external entity vulnerability (CWE-611: Improper Restriction of XML External Entity Reference) affecting Typo3/cms core libraries in the Packagist ecosystem. The issue involves xml external entity in dashboard widget. Remediation is available by upgrading affected packages to version 10.4.10.

CVE-2020-26229 at a Glance

CVE Identifier CVE-2020-26229
GHSA Identifier GHSA-q9cp-mc96-m4w2
Severity LOW
CVSS v3.1 Base Score 3.7
CWE Classification CWE-611: Improper Restriction of XML External Entity Reference
Affected Product Typo3/cms core
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 3.7

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

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

How to Fix CVE-2020-26229

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

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-26229, 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 10.4.10), 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-611: Improper Restriction of XML External Entity Reference, where the product processes an xml document that can contain xml entities with uris that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output. 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

### Problem It has been discovered that RSS widgets are susceptible to XML external entity processing. This vulnerability is reasonable, but is theoretical - it was not possible to actually reproduce the vulnerability with current PHP versions of supported and maintained system distributions. At least with _libxml2_ version 2.9, the processing of XML external entities is disabled per default - and cannot be exploited. Besides that, a valid backend user account is needed. ### Solution Update to TYPO3 version 10.4.10 that fixes the problem described.

CVE-2020-26229 Affected Typo3/cms core Versions

2 component(s)
Fixed Versions:
10.4.10
Product / Package Ecosystem Affected Versions Fixed Version
typo3/cms-core
 Packagist
≥ 10.0.0
< 10.4.10
10.4.10
typo3/cms
 Packagist
≥ 10.0.0
< 10.4.10
10.4.10

References

GitHub Advisory / Wiki ADVISORY
https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-q9cp-mc96-m4w2
NVD — CVE-2020-26229 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-26229
Typo3/cms core Source Repository REPOSITORY
https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2020-26229.yaml
Typo3/cms core Source Repository REPOSITORY
https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2020-26229.yaml
Typo3/cms core Security Information SECURITY
https://typo3.org/security/advisory/typo3-core-sa-2020-012

Frequently Asked Questions

What is CVE-2020-26229?
CVE-2020-26229 is a security vulnerability in Typo3/cms core involving XML External Entity in Dashboard Widget under CWE-611: Improper Restriction of XML External Entity Reference.
Which Typo3/cms core versions are affected?
Affected versions include releases prior to 10.4.10 across affected packages: typo3/cms-core, typo3/cms.
What version fixes CVE-2020-26229?
Upgrading to 10.4.10 (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 10.4.10. Upgrade your dependency to 10.4.10 or later.
Is typo3/cms affected?
Yes, typo3/cms is affected in releases prior to 10.4.10. Upgrade your dependency to 10.4.10 or later.
What is the CVSS score of CVE-2020-26229?
CVE-2020-26229 has a CVSS v3.1 base score of 3.7 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:L.
What CWE is associated with CVE-2020-26229?
CVE-2020-26229 is classified under CWE-611: Improper Restriction of XML External Entity Reference (The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.).
How can I check Packagist dependencies for CVE-2020-26229?
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
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q9cp-mc96-m4w2",
  "modified" : "2024-02-05T11:16:11Z",
  "published" : "2020-11-23T21:18:44Z",
  "aliases" : [ "CVE-2020-26229" ],
  "summary" : "XML External Entity in Dashboard Widget",
  "details" : "### Problem\nIt has been discovered that RSS widgets are susceptible to XML external entity processing.\nThis vulnerability is reasonable, but is theoretical - it was not possible to actually reproduce the vulnerability with current PHP versions of supported and maintained system distributions.\n\nAt least with _libxml2_ version 2.9, the processing of XML external entities is disabled per default - and cannot be exploited. Besides that, a valid backend user account is needed.\n\n### Solution\nUpdate to TYPO3 version 10.4.10 that fixes the problem described.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:L"
  } ],
  "affected" : [ {
    "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"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0"
      }, {
        "fixed" : "10.4.10"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-q9cp-mc96-m4w2"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-26229"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2020-26229.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2020-26229.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://typo3.org/security/advisory/typo3-core-sa-2020-012"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-611" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-11-23T21:16:32Z",
    "nvd_published_at" : "2020-11-23T22:15:12Z"
  }
}