CVE-2021-41559: Quadratic blowup in Convert :xml2array() Vulnerability

MODERATE
Advisory Identifier: GHSA-9fmg-89fx-r33w
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CVSS 6.5
CWE-776
Published
Advisory Summary

CVE-2021-41559 is a MODERATE (CVSS 6.5) :xml2array() vulnerability (CWE-776: Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')) affecting Quadratic blowup in Convert libraries in the Packagist ecosystem. The issue involves :xml2array(). Remediation is available by upgrading affected packages to version 4.10.9.

CVE-2021-41559 at a Glance

CVE Identifier CVE-2021-41559
GHSA Identifier GHSA-9fmg-89fx-r33w
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-776: Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
Affected Product Quadratic blowup in Convert
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 6.5

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:U/C:N/I:N/A:H).

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

How to Fix CVE-2021-41559

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

silverstripe/framework fixed: 4.10.9 
Upgrade silverstripe/framework to 4.10.9
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 silverstripe/framework

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-41559, inspect your project dependencies for Quadratic blowup in Convert:

inspect dependencies for silverstripe/framework

Analyze the terminal output to locate any version of Quadratic blowup in Convert in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.10.9), 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-776: Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion'), where the product uses xml documents and allows their structure to be defined with a document type definition (dtd), but it does not properly control the number of recursive definitions of entities. In Quadratic blowup in Convert, 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

Silverstripe silverstripe/framework 4.x until 4.10.9 has a quadratic blowup in Convert::xml2array() that enables a remote attack via a crafted XML document.

CVE-2021-41559 Affected Quadratic blowup in Convert Versions

1 component(s)
Fixed Versions:
4.10.9
Product / Package Ecosystem Affected Versions Fixed Version
silverstripe/framework
 Packagist
≥ 4.0.0
< 4.10.9
4.10.9

References

NVD — CVE-2021-41559 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-41559
Quadratic blowup in Convert Source Repository REPOSITORY
https://github.com/FriendsOfPHP/security-advisories/blob/master/silverstripe/framework/CVE-2021-41559.yaml
Quadratic blowup in Convert Source Repository REPOSITORY
https://github.com/silverstripe/silverstripe-framework/releases
Quadratic blowup in Convert Release RELEASE
https://www.silverstripe.org/download/security-releases
Quadratic blowup in Convert Release RELEASE
https://www.silverstripe.org/download/security-releases/cve-2021-41559

Frequently Asked Questions

What is CVE-2021-41559?
CVE-2021-41559 is a security vulnerability in Quadratic blowup in Convert involving :xml2array() under CWE-776: Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion').
Which Quadratic blowup in Convert versions are affected?
Affected versions include releases prior to 4.10.9 across affected packages: silverstripe/framework.
What version fixes CVE-2021-41559?
Upgrading to 4.10.9 (or the latest patched release for your respective branch) resolves the vulnerability.
Is silverstripe/framework affected?
Yes, silverstripe/framework is affected in releases prior to 4.10.9. Upgrade your dependency to 4.10.9 or later.
What is the CVSS score of CVE-2021-41559?
CVE-2021-41559 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-41559?
CVE-2021-41559 is classified under CWE-776: Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion') (The product uses XML documents and allows their structure to be defined with a Document Type Definition (DTD), but it does not properly control the number of recursive definitions of entities.).
How can I check Packagist dependencies for CVE-2021-41559?
Run the dependency tree command: 'inspect dependencies for silverstripe/framework'. 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-9fmg-89fx-r33w",
  "modified" : "2022-07-11T19:25:18Z",
  "published" : "2022-06-29T22:39:50Z",
  "aliases" : [ "CVE-2021-41559" ],
  "summary" : "Quadratic blowup in Convert::xml2array()",
  "details" : "Silverstripe silverstripe/framework 4.x until 4.10.9 has a quadratic blowup in Convert::xml2array() that enables a remote attack via a crafted XML document.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "silverstripe/framework"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.10.9"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-41559"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/silverstripe/framework/CVE-2021-41559.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/silverstripe/silverstripe-framework/releases"
  }, {
    "type" : "WEB",
    "url" : "https://www.silverstripe.org/download/security-releases"
  }, {
    "type" : "WEB",
    "url" : "https://www.silverstripe.org/download/security-releases/cve-2021-41559"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-776" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-06-29T22:39:50Z",
    "nvd_published_at" : "2022-06-28T22:15:00Z"
  }
}