CVE-2020-28246: Formio Server-Side Template Injection Vulnerability

CRITICAL
Advisory Identifier: GHSA-52vj-mr2j-f8jh
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CVSS 9.8
CWE-74
Published
Advisory Summary

CVE-2020-28246 is a CRITICAL (CVSS 9.8) server-side template injection vulnerability (CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')) affecting Formio libraries in the npm ecosystem. The issue involves server-side template injection in formio. Remediation is available in the latest vendor maintenance releases.

CVE-2020-28246 at a Glance

CVE Identifier CVE-2020-28246
GHSA Identifier GHSA-52vj-mr2j-f8jh
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Affected Product Formio
Package Ecosystem npm
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-2020-28246

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

formio fixed: Latest secure release 
npm install formio@Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls formio

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2020-28246, inspect your project dependencies using npm:

npm ls formio

Analyze the terminal output to locate any version of Formio in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The npm ls formio command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'), where the product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. In Formio, 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) was discovered in Form.io 2.0.0. This leads to Remote Code Execution during deletion of the default Email template URL. NOTE: the email templating service was removed after 2020. Additionally, the vendor disputes this issue indicating this is sandboxed and only executable by admins.

CVE-2020-28246 Affected Formio Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
formio
npm/formio
npm
≤ 2.0.0

References

NVD — CVE-2020-28246 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-28246
Formio Source Repository REPOSITORY
https://github.com/formio/enterprise-release/blob/master/API-Server-Change-Log.md
Formio Source Repository REPOSITORY
https://github.com/formio/formio

Frequently Asked Questions

What is CVE-2020-28246?
CVE-2020-28246 is a security vulnerability in Formio involving Server-Side Template Injection in formio under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection').
Which Formio versions are affected?
Affected versions include releases prior to current release patches across affected packages: formio.
What version fixes CVE-2020-28246?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is formio affected?
Yes, formio is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2020-28246?
CVE-2020-28246 has a CVSS v3.1 base score of 9.8 (CRITICAL) 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-2020-28246?
CVE-2020-28246 is classified under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.).
How can I check npm dependencies for CVE-2020-28246?
Run the dependency tree command: 'npm ls formio'. 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-52vj-mr2j-f8jh",
  "modified" : "2024-05-03T20:20:17Z",
  "published" : "2022-06-03T00:00:58Z",
  "aliases" : [ "CVE-2020-28246" ],
  "summary" : "Server-Side Template Injection in formio",
  "details" : "A Server-Side Template Injection (SSTI) was discovered in Form.io 2.0.0. This leads to Remote Code Execution during deletion of the default Email template URL. NOTE: the email templating service was removed after 2020. Additionally, the vendor disputes this issue indicating this is sandboxed and only executable by admins.",
  "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" : "npm",
      "name" : "formio"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "2.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-28246"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/formio/enterprise-release/blob/master/API-Server-Change-Log.md"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/formio/formio"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-74" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-06-03T22:20:22Z",
    "nvd_published_at" : "2022-06-02T14:15:00Z"
  }
}