CVE-2021-33318: IpMatcher Improper Input Validation Vulnerability

CRITICAL
Advisory Identifier: GHSA-qj93-37f5-mr29
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CVSS 9.8
CWE-20 CWE-704
Published
Advisory Summary

CVE-2021-33318 is a CRITICAL (CVSS 9.8) improper input validation vulnerability (CWE-20: Improper Input Validation) affecting IpMatcher libraries in the NuGet ecosystem. The issue involves improper input validation in ipmatcher. Remediation is available by upgrading affected packages to version 1.0.4.2.

CVE-2021-33318 at a Glance

CVE Identifier CVE-2021-33318
GHSA Identifier GHSA-qj93-37f5-mr29
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-20: Improper Input Validation
Affected Product IpMatcher
Package Ecosystem NuGet
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-2021-33318

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

IpMatcher fixed: 1.0.4.2 
Upgrade IpMatcher to 1.0.4.2
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 IpMatcher

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-33318, inspect your project dependencies for IpMatcher:

inspect dependencies for IpMatcher

Analyze the terminal output to locate any version of IpMatcher in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.0.4.2), 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-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In IpMatcher, 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

An Input Validation Vulnerability exists in Joel Christner .NET C# packages WatsonWebserver, IpMatcher 1.0.4.1 and below (IpMatcher) and 4.1.3 and below (WatsonWebserver) due to insufficient validation of input IP addresses and netmasks against the internal Matcher list of IP addresses and subnets.

CVE-2021-33318 Affected IpMatcher Versions

1 component(s)
Fixed Versions:
1.0.4.2
Product / Package Ecosystem Affected Versions Fixed Version
IpMatcher
nuget/IpMatcher
NuGet
< 1.0.4.2
1.0.4.2

References

NVD — CVE-2021-33318 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-33318
Security Fix Commit FIX COMMIT
https://github.com/jchristn/IpMatcher/commit/81d77c2f33aa912dbd032b34b9e184fc6e041d89
IpMatcher Source Repository REPOSITORY
https://github.com/jchristn/IpMatcher
IpMatcher Source Repository REPOSITORY
https://github.com/jchristn/WatsonWebserver
GitHub Advisory / Wiki ADVISORY
https://github.com/kaoudis/advisories/blob/main/0-2021.md

Frequently Asked Questions

What is CVE-2021-33318?
CVE-2021-33318 is a security vulnerability in IpMatcher involving Improper Input Validation in IpMatcher under CWE-20: Improper Input Validation.
Which IpMatcher versions are affected?
Affected versions include releases prior to 1.0.4.2 across affected packages: IpMatcher.
What version fixes CVE-2021-33318?
Upgrading to 1.0.4.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is IpMatcher affected?
Yes, IpMatcher is affected in releases prior to 1.0.4.2. Upgrade your dependency to 1.0.4.2 or later.
What is the CVSS score of CVE-2021-33318?
CVE-2021-33318 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-2021-33318?
CVE-2021-33318 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check NuGet dependencies for CVE-2021-33318?
Run the dependency tree command: 'inspect dependencies for IpMatcher'. 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-qj93-37f5-mr29",
  "modified" : "2022-05-26T21:21:26Z",
  "published" : "2022-05-17T00:00:35Z",
  "aliases" : [ "CVE-2021-33318" ],
  "summary" : "Improper Input Validation in IpMatcher",
  "details" : "An Input Validation Vulnerability exists in Joel Christner .NET C# packages WatsonWebserver, IpMatcher 1.0.4.1 and below (IpMatcher) and 4.1.3 and below (WatsonWebserver) due to insufficient validation of input IP addresses and netmasks against the internal Matcher list of IP addresses and subnets.",
  "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" : "NuGet",
      "name" : "IpMatcher"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.0.4.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.0.4.1"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-33318"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/jchristn/IpMatcher/commit/81d77c2f33aa912dbd032b34b9e184fc6e041d89"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jchristn/IpMatcher"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/jchristn/WatsonWebserver"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/kaoudis/advisories/blob/main/0-2021.md"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20", "CWE-704" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-05-25T19:26:55Z",
    "nvd_published_at" : "2022-05-16T16:15:00Z"
  }
}