CVE-2022-23516: Loofah Uncontrolled Recursion Vulnerability

HIGH
Advisory Identifier: GHSA-3x8r-x6xp-q4vm
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CVSS 7.5
CWE-674
Published
Advisory Summary

CVE-2022-23516 is a HIGH (CVSS 7.5) uncontrolled recursion vulnerability (CWE-674: Uncontrolled Recursion) affecting Loofah libraries in the RubyGems ecosystem. The issue involves uncontrolled recursion in loofah. Remediation is available by upgrading affected packages to version 2.19.1.

CVE-2022-23516 at a Glance

CVE Identifier CVE-2022-23516
GHSA Identifier GHSA-3x8r-x6xp-q4vm
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-674: Uncontrolled Recursion
Affected Product Loofah
Package Ecosystem RubyGems
Published Date
Last Updated

Security Impact

CVSS: 7.5

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:N/I:N/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 None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2022-23516

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

loofah fixed: 2.19.1 
Upgrade loofah to 2.19.1
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 loofah

How to Check if You Are Affected

To determine whether your application is affected by CVE-2022-23516, inspect your project dependencies for Loofah:

inspect dependencies for loofah

Analyze the terminal output to locate any version of Loofah in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.19.1), 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-674: Uncontrolled Recursion, where the product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. In Loofah, 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

## Summary Loofah `>= 2.2.0, < 2.19.1` uses recursion for sanitizing `CDATA` sections, making it susceptible to stack exhaustion and raising a `SystemStackError` exception. This may lead to a denial of service through CPU resource consumption. ## Mitigation Upgrade to Loofah `>= 2.19.1`. Users who are unable to upgrade may be able to mitigate this vulnerability by limiting the length of the strings that are sanitized. ## Severity The Loofah maintainers have evaluated this as [High Severity 7.5 (CVSS3.1)](https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). ## References - [CWE - CWE-674: Uncontrolled Recursion (4.9)](https://cwe.mitre.org/data/definitions/674.html)

CVE-2022-23516 Affected Loofah Versions

1 component(s)
Fixed Versions:
2.19.1
Product / Package Ecosystem Affected Versions Fixed Version
loofah
gem/loofah
RubyGems
≥ 2.2.0
< 2.19.1
2.19.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/flavorjones/loofah/security/advisories/GHSA-3x8r-x6xp-q4vm
NVD — CVE-2022-23516 NVD
https://nvd.nist.gov/vuln/detail/CVE-2022-23516
Security Fix Commit FIX COMMIT
https://github.com/flavorjones/loofah/commit/86f7f6364491b0099d215db858ecdc0c89ded040
Loofah Source Repository REPOSITORY
https://github.com/flavorjones/loofah
Loofah Source Repository REPOSITORY
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/loofah/CVE-2022-23516.yml
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2023/09/msg00011.html
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2024/09/msg00044.html

Frequently Asked Questions

What is CVE-2022-23516?
CVE-2022-23516 is a security vulnerability in Loofah involving Uncontrolled Recursion in Loofah under CWE-674: Uncontrolled Recursion.
Which Loofah versions are affected?
Affected versions include releases prior to 2.19.1 across affected packages: loofah.
What version fixes CVE-2022-23516?
Upgrading to 2.19.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is loofah affected?
Yes, loofah is affected in releases prior to 2.19.1. Upgrade your dependency to 2.19.1 or later.
What is the CVSS score of CVE-2022-23516?
CVE-2022-23516 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2022-23516?
CVE-2022-23516 is classified under CWE-674: Uncontrolled Recursion (The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.).
How can I check RubyGems dependencies for CVE-2022-23516?
Run the dependency tree command: 'inspect dependencies for loofah'. 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-3x8r-x6xp-q4vm",
  "modified" : "2025-11-04T16:41:06Z",
  "published" : "2022-12-13T17:40:50Z",
  "aliases" : [ "CVE-2022-23516" ],
  "summary" : "Uncontrolled Recursion in Loofah",
  "details" : "## Summary\n\nLoofah `>= 2.2.0, < 2.19.1` uses recursion for sanitizing `CDATA` sections, making it susceptible to stack exhaustion and raising a `SystemStackError` exception.  This may lead to a denial of service through CPU resource consumption.\n\n\n## Mitigation\n\nUpgrade to Loofah `>= 2.19.1`.\n\nUsers who are unable to upgrade may be able to mitigate this vulnerability by limiting the length of the strings that are sanitized.\n\n\n## Severity\n\nThe Loofah maintainers have evaluated this as [High Severity 7.5 (CVSS3.1)](https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).\n\n\n## References\n\n- [CWE - CWE-674: Uncontrolled Recursion (4.9)](https://cwe.mitre.org/data/definitions/674.html)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "loofah"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.2.0"
      }, {
        "fixed" : "2.19.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/flavorjones/loofah/security/advisories/GHSA-3x8r-x6xp-q4vm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2022-23516"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/flavorjones/loofah/commit/86f7f6364491b0099d215db858ecdc0c89ded040"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/flavorjones/loofah"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/loofah/CVE-2022-23516.yml"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2023/09/msg00011.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2024/09/msg00044.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-674" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-12-13T17:40:50Z",
    "nvd_published_at" : "2022-12-14T14:15:00Z"
  }
}