CVE-2021-21359: Typo3/cms core Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-4p9g-qgx9-397p
CVSS 5.9
CWE-405 CWE-674
Published
Advisory Summary

CVE-2021-21359 is a MODERATE (CVSS 5.9) denial of service vulnerability (CWE-405: Asymmetric Resource Consumption (Amplification)) affecting Typo3/cms core libraries in the Packagist ecosystem. The issue involves denial of service in page error handling. Remediation is available by upgrading affected packages to version 10.4.14, 11.1.1, 9.5.25.

CVE-2021-21359 at a Glance

CVE Identifier CVE-2021-21359
GHSA Identifier GHSA-4p9g-qgx9-397p
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-405: Asymmetric Resource Consumption (Amplification)
Affected Product Typo3/cms core
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 5.9

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

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

How to Fix CVE-2021-21359

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: 10.4.14
Upgrade typo3/cms-core to 10.4.14
typo3/cms-core fixed: 11.1.1
Upgrade typo3/cms-core to 11.1.1
typo3/cms-core fixed: 9.5.25
Upgrade typo3/cms-core to 9.5.25
typo3/cms fixed: 10.4.14
Upgrade typo3/cms to 10.4.14
typo3/cms fixed: 11.1.1
Upgrade typo3/cms to 11.1.1
typo3/cms fixed: 9.5.25
Upgrade typo3/cms to 9.5.25
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-2021-21359, 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 10.4.14), 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-405: Asymmetric Resource Consumption (Amplification), where the product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is "asymmetric.". 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:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C` (5.5) > * CWE-405, CWE-674 > * Status: **DRAFT** ### Problem Requesting invalid or non-existing resources via HTTP triggers the page error handler which again could retrieve content to be shown as error message from another page. This leads to a scenario in which the application is calling itself recursively - amplifying the impact of the initial attack until the limits of the web server are exceeded. ### Solution Update to TYPO3 versions 9.5.25, 10.4.14, 11.1.1 that fix the problem described. ### Credits Thanks to Paul Keller, Mathias Bolt Lesniak and Kay Strobach who reported this issue and to TYPO3 framework merger Frank Nägler and to TYPO3 security team member Torben Hansen who fixed the issue. ### References * [TYPO3-CORE-SA-2021-005](https://typo3.org/security/advisory/typo3-core-sa-2021-005)

CVE-2021-21359 Affected Typo3/cms core Versions

6 component(s)
Fixed Versions:
10.4.1411.1.19.5.25
Product / Package Ecosystem Affected Versions Fixed Version
typo3/cms-core
Packagist
≥ 10.0.0
< 10.4.14
10.4.14
typo3/cms-core
Packagist
≥ 11.0.0
< 11.1.1
11.1.1
typo3/cms-core
Packagist
≥ 9.0.0
< 9.5.25
9.5.25
typo3/cms
Packagist
≥ 10.0.0
< 10.4.14
10.4.14
typo3/cms
Packagist
≥ 11.0.0
< 11.1.1
11.1.1
typo3/cms
Packagist
≥ 9.0.0
< 9.5.25
9.5.25

References

Frequently Asked Questions

What is CVE-2021-21359?
CVE-2021-21359 is a security vulnerability in Typo3/cms core involving Denial of Service in Page Error Handling under CWE-405: Asymmetric Resource Consumption (Amplification).
Which Typo3/cms core versions are affected?
Affected versions include releases prior to 10.4.14, 11.1.1, 9.5.25 across affected packages: typo3/cms-core, typo3/cms.
What version fixes CVE-2021-21359?
Upgrading to 10.4.14, 11.1.1, 9.5.25 (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 10.4.14, 11.1.1, 9.5.25. Upgrade your dependency to 10.4.14, 11.1.1, 9.5.25 or later.
Is typo3/cms affected?
Yes, typo3/cms is affected in releases prior to 10.4.14, 11.1.1, 9.5.25. Upgrade your dependency to 10.4.14, 11.1.1, 9.5.25 or later.
What is the CVSS score of CVE-2021-21359?
CVE-2021-21359 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C.
What CWE is associated with CVE-2021-21359?
CVE-2021-21359 is classified under CWE-405: Asymmetric Resource Consumption (Amplification) (The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is "asymmetric.").
How can I check Packagist dependencies for CVE-2021-21359?
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-4p9g-qgx9-397p",
  "modified" : "2024-02-07T18:50:34Z",
  "published" : "2021-03-23T01:54:09Z",
  "aliases" : [ "CVE-2021-21359" ],
  "summary" : "Denial of Service in Page Error Handling",
  "details" : "> ### Meta\n> * CVSS:  `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C` (5.5)\n> * CWE-405, CWE-674\n> * Status: **DRAFT**\n\n### Problem\nRequesting invalid or non-existing resources via HTTP triggers the page error handler which again could retrieve content  to be shown as error message from another page. This leads to a scenario in which the application is calling itself recursively - amplifying the impact of the initial attack until the limits of the web server are exceeded.\n\n### Solution\nUpdate to TYPO3 versions 9.5.25, 10.4.14, 11.1.1 that fix the problem described.\n\n### Credits\nThanks to Paul Keller, Mathias Bolt Lesniak and Kay Strobach who reported this issue and to TYPO3 framework merger Frank Nägler and to TYPO3 security team member Torben Hansen who fixed the issue.\n\n### References\n* [TYPO3-CORE-SA-2021-005](https://typo3.org/security/advisory/typo3-core-sa-2021-005)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0"
      }, {
        "fixed" : "10.4.14"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0"
      }, {
        "fixed" : "11.1.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.5.25"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0"
      }, {
        "fixed" : "10.4.14"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0"
      }, {
        "fixed" : "11.1.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.5.25"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21359"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2021-21359.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2021-21359.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://packagist.org/packages/typo3/cms-core"
  }, {
    "type" : "WEB",
    "url" : "https://typo3.org/security/advisory/typo3-core-sa-2021-005"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-405", "CWE-674" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-03-23T01:42:10Z",
    "nvd_published_at" : "2021-03-23T02:15:00Z"
  }
}