CVE-2021-44618: Nystudio107/craft seomatic Server-side Template Injection Vulnerability

HIGH
Advisory Identifier: GHSA-m3xv-x3ph-mq22
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CVSS 9.8
CWE-94
Published
Advisory Summary

CVE-2021-44618 is a HIGH (CVSS 9.8) server-side template injection vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Nystudio107/craft seomatic libraries in the Packagist ecosystem. The issue involves server-side template injection in nystudio107/craft-seomatic. Remediation is available by upgrading affected packages to version 3.4.12.

CVE-2021-44618 at a Glance

CVE Identifier CVE-2021-44618
GHSA Identifier GHSA-m3xv-x3ph-mq22
Severity HIGH
CVSS v3.1 Base Score 9.8
CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')
Affected Product Nystudio107/craft seomatic
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

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

How to Fix CVE-2021-44618

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: 3.4.12 
Upgrade nystudio107/craft-seomatic to 3.4.12
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-2021-44618, 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 3.4.12), 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-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. 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 Server-side Template Injection (SSTI) vulnerability exists in Nystudio107 Seomatic prior to 3.4.12 in src/helpers/UrlHelper.php via the host header.

CVE-2021-44618 Affected Nystudio107/craft seomatic Versions

1 component(s)
Fixed Versions:
3.4.12
Product / Package Ecosystem Affected Versions Fixed Version
nystudio107/craft-seomatic
 Packagist
< 3.4.12
3.4.12

References

NVD — CVE-2021-44618 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-44618
Security Fix Commit FIX COMMIT
https://github.com/nystudio107/craft-seomatic/commit/0c5c0c0e0cb61000d12ec55ebf174745a5bf6469
Nystudio107/craft seomatic Source Repository REPOSITORY
https://github.com/nystudio107/craft-seomatic
Nystudio107/craft seomatic Release RELEASE
https://github.com/nystudio107/craft-seomatic/releases/tag/3.4.12

Frequently Asked Questions

What is CVE-2021-44618?
CVE-2021-44618 is a security vulnerability in Nystudio107/craft seomatic involving Server-side Template Injection in nystudio107/craft-seomatic under CWE-94: Improper Control of Generation of Code ('Code Injection').
Which Nystudio107/craft seomatic versions are affected?
Affected versions include releases prior to 3.4.12 across affected packages: nystudio107/craft-seomatic.
What version fixes CVE-2021-44618?
Upgrading to 3.4.12 (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 3.4.12. Upgrade your dependency to 3.4.12 or later.
What is the CVSS score of CVE-2021-44618?
CVE-2021-44618 has a CVSS v3.1 base score of 9.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2021-44618?
CVE-2021-44618 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).
How can I check Packagist dependencies for CVE-2021-44618?
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-m3xv-x3ph-mq22",
  "modified" : "2022-03-24T13:44:50Z",
  "published" : "2022-03-12T00:00:34Z",
  "aliases" : [ "CVE-2021-44618" ],
  "summary" : "Server-side Template Injection in nystudio107/craft-seomatic",
  "details" : "A Server-side Template Injection (SSTI) vulnerability exists in Nystudio107 Seomatic prior to 3.4.12 in src/helpers/UrlHelper.php via the host header.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "nystudio107/craft-seomatic"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.4.12"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-44618"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nystudio107/craft-seomatic/commit/0c5c0c0e0cb61000d12ec55ebf174745a5bf6469"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nystudio107/craft-seomatic"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nystudio107/craft-seomatic/releases/tag/3.4.12"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-03-14T23:21:34Z",
    "nvd_published_at" : "2022-03-11T16:15:00Z"
  }
}