CVE-2021-21328: Github.com/vapor/vapor Vapor's Metrics Integration Could Cause Vulnerability

MODERATE
Advisory Identifier: GHSA-gcj9-jj38-hwmc
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CVSS 5.3
CWE-400
Published
Advisory Summary

CVE-2021-21328 is a MODERATE (CVSS 5.3) vapor's metrics integration could cause vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Github.com/vapor/vapor libraries in the SwiftURL ecosystem. The issue involves vapor's metrics integration could cause a system drain. Remediation is available by upgrading affected packages to version 4.40.1.

CVE-2021-21328 at a Glance

CVE Identifier CVE-2021-21328
GHSA Identifier GHSA-gcj9-jj38-hwmc
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Github.com/vapor/vapor
Package Ecosystem SwiftURL
Published Date
Last Updated

Security Impact

CVSS: 5.3

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:L).

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 Low (A:L)

How to Fix CVE-2021-21328

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

github.com/vapor/vapor fixed: 4.40.1 
Upgrade github.com/vapor/vapor to 4.40.1
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 github.com/vapor/vapor

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-21328, inspect your project dependencies for Github.com/vapor/vapor:

inspect dependencies for github.com/vapor/vapor

Analyze the terminal output to locate any version of Github.com/vapor/vapor in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.40.1), 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-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Github.com/vapor/vapor, 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

### Impact This is a DoS attack against anyone who Bootstraps a metrics backend for their Vapor app with the following attack vector: 1. send unlimited requests against a vapor instance with different paths. this will create “unlimited” counters and timers, which will eventually drain the system. 2. downstream services might suffer from this attack as well by being spammed with error paths ### Patches This has been patched in 4.40.1. The `DefaultResponder` will rewrite any undefined route paths for to `vapor_route_undefined` to avoid unlimited counters. ### Workarounds Don't bootstrap a metrics system or upgrade to 4.40.1 ### For more information If you have any questions or comments about this advisory: * Open an issue in [Vapor](https://github.com/vapor/vapor) * Ask in [Discord](http://vapor.team)

CVE-2021-21328 Affected Github.com/vapor/vapor Versions

1 component(s)
Fixed Versions:
4.40.1
Product / Package Ecosystem Affected Versions Fixed Version
github.com/vapor/vapor
 SwiftURL
< 4.40.1
4.40.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vapor/vapor/security/advisories/GHSA-gcj9-jj38-hwmc
NVD — CVE-2021-21328 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-21328
Security Fix Commit FIX COMMIT
https://github.com/vapor/vapor/commit/e3aa712508db2854ac0ab905696c65fd88fa7e23
Github.com/vapor/vapor Source Repository REPOSITORY
https://github.com/vapor/vapor
Github.com/vapor/vapor Release RELEASE
https://github.com/vapor/vapor/releases/tag/4.40.1
vapor.codes WEB
https://vapor.codes

Frequently Asked Questions

What is CVE-2021-21328?
CVE-2021-21328 is a security vulnerability in Github.com/vapor/vapor involving Vapor's Metrics integration could cause a system drain under CWE-400: Uncontrolled Resource Consumption.
Which Github.com/vapor/vapor versions are affected?
Affected versions include releases prior to 4.40.1 across affected packages: github.com/vapor/vapor.
What version fixes CVE-2021-21328?
Upgrading to 4.40.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/vapor/vapor affected?
Yes, github.com/vapor/vapor is affected in releases prior to 4.40.1. Upgrade your dependency to 4.40.1 or later.
What is the CVSS score of CVE-2021-21328?
CVE-2021-21328 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2021-21328?
CVE-2021-21328 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check SwiftURL dependencies for CVE-2021-21328?
Run the dependency tree command: 'inspect dependencies for github.com/vapor/vapor'. 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-gcj9-jj38-hwmc",
  "modified" : "2023-06-09T19:31:47Z",
  "published" : "2023-06-09T19:31:47Z",
  "aliases" : [ "CVE-2021-21328" ],
  "summary" : "Vapor's Metrics integration could cause a system drain",
  "details" : "### Impact\nThis is a DoS attack against anyone who Bootstraps a metrics backend for their Vapor app with the following attack vector:\n\n1. send unlimited requests against a vapor instance with different paths. this will create “unlimited” counters and timers, which will eventually drain the system.\n2. downstream services might suffer from this attack as well by being spammed with error paths\n\n### Patches\nThis has been patched in 4.40.1. The `DefaultResponder` will rewrite any undefined route paths for to `vapor_route_undefined` to avoid unlimited counters.\n\n### Workarounds\nDon't bootstrap a metrics system or upgrade to 4.40.1\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [Vapor](https://github.com/vapor/vapor)\n* Ask in [Discord](http://vapor.team)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "SwiftURL",
      "name" : "github.com/vapor/vapor"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.40.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.40.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vapor/vapor/security/advisories/GHSA-gcj9-jj38-hwmc"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21328"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vapor/vapor/commit/e3aa712508db2854ac0ab905696c65fd88fa7e23"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vapor/vapor"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vapor/vapor/releases/tag/4.40.1"
  }, {
    "type" : "WEB",
    "url" : "https://vapor.codes"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-06-09T19:31:47Z",
    "nvd_published_at" : "2021-02-26T02:15:00Z"
  }
}