CVE-2018-12026: Passenger Phusion Passenger SpawningKit Contains Arbitrary Vulnerability

CRITICAL
Advisory Identifier: GHSA-7cv3-gvmc-8mq5
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CVSS 9.8
CWE-59
Published
Advisory Summary

CVE-2018-12026 is a CRITICAL (CVSS 9.8) phusion passenger spawningkit contains arbitrary vulnerability (CWE-59: Improper Link Resolution Before File Access ('Link Following')) affecting Passenger libraries in the RubyGems ecosystem. The issue involves phusion passenger spawningkit contains arbitrary read/write vulnerability. Remediation is available by upgrading affected packages to version 5.3.2.

CVE-2018-12026 at a Glance

CVE Identifier CVE-2018-12026
GHSA Identifier GHSA-7cv3-gvmc-8mq5
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-59: Improper Link Resolution Before File Access ('Link Following')
Affected Product Passenger
Package Ecosystem RubyGems
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:3.0/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-2018-12026

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

passenger fixed: 5.3.2 
Upgrade passenger to 5.3.2
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 passenger

How to Check if You Are Affected

To determine whether your application is affected by CVE-2018-12026, inspect your project dependencies for Passenger:

inspect dependencies for passenger

Analyze the terminal output to locate any version of Passenger in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.3.2), 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-59: Improper Link Resolution Before File Access ('Link Following'), where the product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. In Passenger, 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

During the spawning of a malicious Passenger-managed application, SpawningKit in Phusion Passenger 5.3.x before 5.3.2 allows such applications to replace key files or directories in the spawning communication directory with symlinks. This then could result in arbitrary reads and writes, which in turn can result in information disclosure and privilege escalation.

CVE-2018-12026 Affected Passenger Versions

1 component(s)
Fixed Versions:
5.3.2
Product / Package Ecosystem Affected Versions Fixed Version
passenger
gem/passenger
RubyGems
≥ 5.3.0
< 5.3.2
5.3.2

References

NVD — CVE-2018-12026 NVD
https://nvd.nist.gov/vuln/detail/CVE-2018-12026
Security Fix Commit FIX COMMIT
https://github.com/phusion/passenger/commit/fd3717a3cd357aa0e80e1e81d4dc94a1eaf928f1
Passenger Security Information SECURITY
https://blog.phusion.nl/2018/06/12/passenger-5-3-2-various-security-fixes
blog.phusion.nl/passenger-5-3-2 WEB
https://blog.phusion.nl/passenger-5-3-2
Passenger Source Repository REPOSITORY
https://github.com/phusion/passenger
Passenger Source Repository REPOSITORY
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/passenger/CVE-2018-12026.yml
Passenger Security Information SECURITY
https://security.gentoo.org/glsa/201807-02

Frequently Asked Questions

What is CVE-2018-12026?
CVE-2018-12026 is a security vulnerability in Passenger involving Phusion Passenger SpawningKit Contains Arbitrary Read/Write Vulnerability under CWE-59: Improper Link Resolution Before File Access ('Link Following').
Which Passenger versions are affected?
Affected versions include releases prior to 5.3.2 across affected packages: passenger.
What version fixes CVE-2018-12026?
Upgrading to 5.3.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is passenger affected?
Yes, passenger is affected in releases prior to 5.3.2. Upgrade your dependency to 5.3.2 or later.
What is the CVSS score of CVE-2018-12026?
CVE-2018-12026 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2018-12026?
CVE-2018-12026 is classified under CWE-59: Improper Link Resolution Before File Access ('Link Following') (The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.).
How can I check RubyGems dependencies for CVE-2018-12026?
Run the dependency tree command: 'inspect dependencies for passenger'. 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-7cv3-gvmc-8mq5",
  "modified" : "2023-07-03T21:44:25Z",
  "published" : "2022-05-14T01:27:14Z",
  "aliases" : [ "CVE-2018-12026" ],
  "summary" : "Phusion Passenger SpawningKit Contains Arbitrary Read/Write Vulnerability",
  "details" : "During the spawning of a malicious Passenger-managed application, SpawningKit in Phusion Passenger 5.3.x before 5.3.2 allows such applications to replace key files or directories in the spawning communication directory with symlinks. This then could result in arbitrary reads and writes, which in turn can result in information disclosure and privilege escalation.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "passenger"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.3.0"
      }, {
        "fixed" : "5.3.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-12026"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/phusion/passenger/commit/fd3717a3cd357aa0e80e1e81d4dc94a1eaf928f1"
  }, {
    "type" : "WEB",
    "url" : "https://blog.phusion.nl/2018/06/12/passenger-5-3-2-various-security-fixes"
  }, {
    "type" : "WEB",
    "url" : "https://blog.phusion.nl/passenger-5-3-2"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/phusion/passenger"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/passenger/CVE-2018-12026.yml"
  }, {
    "type" : "WEB",
    "url" : "https://security.gentoo.org/glsa/201807-02"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-59" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-06-09T23:01:47Z",
    "nvd_published_at" : "2018-06-17T20:29:00Z"
  }
}