CVE-2021-41750: Nystudio107/craft seomatic Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-6hjc-m38h-7jhh
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2021-41750 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Nystudio107/craft seomatic libraries in the Packagist ecosystem. The issue involves cross-site scripting in seomatic plugin. Remediation is available by upgrading affected packages to version 3.4.11.

CVE-2021-41750 at a Glance

CVE Identifier CVE-2021-41750
GHSA Identifier GHSA-6hjc-m38h-7jhh
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 Nystudio107/craft seomatic
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-2021-41750

To remediate this vulnerability, upgrade all affected Nystudio107/craft seomatic dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

nystudio107/craft-seomatic fixed: 3.4.11 
Upgrade nystudio107/craft-seomatic to 3.4.11
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 nystudio107/craft-seomatic

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-41750, inspect your project dependencies for Nystudio107/craft seomatic:

inspect dependencies for nystudio107/craft-seomatic

Analyze the terminal output to locate any version of Nystudio107/craft seomatic in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.4.11), 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 Nystudio107/craft seomatic, 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

A cross-site scripting (XSS) vulnerability in the SEOmatic plugin 3.4.10 for Craft CMS 3 allows remote attackers to inject arbitrary web script via a GET to /index.php?action=seomatic/file/seo-file-link with url parameter containing the base64 encoded URL of a malicious web page / file and fileName parameter containing an arbitrary filename with the intended content-type to be rendered in the user's browser as the extension.

CVE-2021-41750 Affected Nystudio107/craft seomatic Versions

1 component(s)
Fixed Versions:
3.4.11
Product / Package Ecosystem Affected Versions Fixed Version
nystudio107/craft-seomatic
 Packagist
< 3.4.11
3.4.11

References

NVD — CVE-2021-41750 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-41750
Security Fix Commit FIX COMMIT
https://github.com/nystudio107/craft-seomatic/commit/4e46b792ce973ac0c652fb330055f41aca1981c8
Security Fix Commit FIX COMMIT
https://github.com/nystudio107/craft-seomatic/commit/5f2cdc7c39e0a4bfb60d2f84131508f0a87b2873
Nystudio107/craft seomatic Source Repository REPOSITORY
https://github.com/nystudio107/craft-seomatic
Nystudio107/craft seomatic Source Repository REPOSITORY
https://github.com/nystudio107/craft-seomatic/blob/develop/CHANGELOG.md

Frequently Asked Questions

What is CVE-2021-41750?
CVE-2021-41750 is a security vulnerability in Nystudio107/craft seomatic involving Cross-site Scripting in SEOmatic plugin under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Nystudio107/craft seomatic versions are affected?
Affected versions include releases prior to 3.4.11 across affected packages: nystudio107/craft-seomatic.
What version fixes CVE-2021-41750?
Upgrading to 3.4.11 (or the latest patched release for your respective branch) resolves the vulnerability.
Is nystudio107/craft-seomatic affected?
Yes, nystudio107/craft-seomatic is affected in releases prior to 3.4.11. Upgrade your dependency to 3.4.11 or later.
What is the CVSS score of CVE-2021-41750?
CVE-2021-41750 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-2021-41750?
CVE-2021-41750 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-2021-41750?
Run the dependency tree command: 'inspect dependencies for nystudio107/craft-seomatic'. 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-6hjc-m38h-7jhh",
  "modified" : "2022-06-20T22:38:22Z",
  "published" : "2022-06-13T00:00:19Z",
  "aliases" : [ "CVE-2021-41750" ],
  "summary" : "Cross-site Scripting in SEOmatic plugin",
  "details" : "A cross-site scripting (XSS) vulnerability in the SEOmatic plugin 3.4.10 for Craft CMS 3 allows remote attackers to inject arbitrary web script via a GET to /index.php?action=seomatic/file/seo-file-link with url parameter containing the base64 encoded URL of a malicious web page / file and fileName parameter containing an arbitrary filename with the intended content-type to be rendered in the user's browser as the extension.",
  "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" : "nystudio107/craft-seomatic"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.4.11"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-41750"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nystudio107/craft-seomatic/commit/4e46b792ce973ac0c652fb330055f41aca1981c8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nystudio107/craft-seomatic/commit/5f2cdc7c39e0a4bfb60d2f84131508f0a87b2873"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nystudio107/craft-seomatic"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nystudio107/craft-seomatic/blob/develop/CHANGELOG.md"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-06-20T22:38:22Z",
    "nvd_published_at" : "2022-06-12T12:15:00Z"
  }
}