CVE-2021-46433: Fenom/fenom Sandbox Bypass Vulnerability

CRITICAL
Advisory Identifier: GHSA-674v-3g2w-84gx
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CVSS 10.0
Published
Advisory Summary

CVE-2021-46433 is a CRITICAL (CVSS 10.0) sandbox bypass vulnerability (General Security Weakness) affecting Fenom/fenom libraries in the Packagist ecosystem. The issue involves sandbox bypass in fenom. Remediation is available in the latest vendor maintenance releases.

CVE-2021-46433 at a Glance

CVE Identifier CVE-2021-46433
GHSA Identifier GHSA-674v-3g2w-84gx
Severity CRITICAL
CVSS v3.1 Base Score 10.0
CWE Classification General Security Weakness
Affected Product Fenom/fenom
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 10.0

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:C/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 Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2021-46433

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

fenom/fenom fixed: Latest secure release 
Upgrade fenom/fenom to 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: 

inspect dependencies for fenom/fenom

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-46433, inspect your project dependencies for Fenom/fenom:

inspect dependencies for fenom/fenom

Analyze the terminal output to locate any version of Fenom/fenom 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: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under General Security Weakness. In Fenom/fenom, 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

In fenom 2.12.1 and before, there is a way in fenom/src/Fenom/Template.php function getTemplateCode()to bypass sandbox to execute arbitrary PHP code when disable_native_funcs is true.

CVE-2021-46433 Affected Fenom/fenom Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
fenom/fenom
 Packagist
≤ 2.12.1

References

NVD — CVE-2021-46433 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-46433
Fenom/fenom Source Repository REPOSITORY
https://github.com/fenom-template/fenom/issues/331
Fenom/fenom Source Repository REPOSITORY
https://github.com/fenom-template/fenom

Frequently Asked Questions

What is CVE-2021-46433?
CVE-2021-46433 is a security vulnerability in Fenom/fenom involving Sandbox bypass in fenom under General Security Weakness.
Which Fenom/fenom versions are affected?
Affected versions include releases prior to current release patches across affected packages: fenom/fenom.
What version fixes CVE-2021-46433?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is fenom/fenom affected?
Yes, fenom/fenom 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-2021-46433?
CVE-2021-46433 has a CVSS v3.1 base score of 10.0 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2021-46433?
CVE-2021-46433 is classified under General Security Weakness.
How can I check Packagist dependencies for CVE-2021-46433?
Run the dependency tree command: 'inspect dependencies for fenom/fenom'. 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-674v-3g2w-84gx",
  "modified" : "2022-04-05T18:52:09Z",
  "published" : "2022-03-29T00:01:15Z",
  "aliases" : [ "CVE-2021-46433" ],
  "summary" : "Sandbox bypass in fenom",
  "details" : "In fenom 2.12.1 and before, there is a way in fenom/src/Fenom/Template.php function getTemplateCode()to bypass sandbox to execute arbitrary PHP code when disable_native_funcs is true.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "fenom/fenom"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "2.12.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-46433"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fenom-template/fenom/issues/331"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/fenom-template/fenom"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-03-30T19:57:38Z",
    "nvd_published_at" : "2022-03-28T11:15:00Z"
  }
}