CVE-2021-43309: Uri template lite Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-chw2-6c7r-37p7
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CVSS 5.9
CWE-1333 CWE-697
Published
Advisory Summary

CVE-2021-43309 is a MODERATE (CVSS 5.9) denial of service vulnerability (CWE-1333: Inefficient Regular Expression Complexity) affecting Uri template lite libraries in the npm ecosystem. The issue involves uri-template-lite regular expression denial of service. Remediation is available by upgrading affected packages to version 22.9.0.

CVE-2021-43309 at a Glance

CVE Identifier CVE-2021-43309
GHSA Identifier GHSA-chw2-6c7r-37p7
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-1333: Inefficient Regular Expression Complexity
Affected Product Uri template lite
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
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-2021-43309

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

uri-template-lite fixed: 22.9.0 
npm install uri-template-lite@22.9.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls uri-template-lite

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-43309, inspect your project dependencies using npm:

npm ls uri-template-lite

Analyze the terminal output to locate any version of Uri template lite in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 22.9.0), your application is affected.

Note: The npm ls uri-template-lite command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1333: Inefficient Regular Expression Complexity, where the product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential. In Uri template lite, 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 exponential ReDoS (Regular Expression Denial of Service) can be triggered in the uri-template-lite npm package, when an attacker is able to supply arbitrary input to the "URI.expand" method.

CVE-2021-43309 Affected Uri template lite Versions

1 component(s)
Fixed Versions:
22.9.0
Product / Package Ecosystem Affected Versions Fixed Version
uri-template-lite
npm/uri-template-lite
npm
< 22.9.0
22.9.0

References

NVD — CVE-2021-43309 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-43309
Security Fix Commit FIX COMMIT
https://github.com/litejs/uri-template-lite/commit/cbeec2b2a275d819fb534137a155df14729706f8
Uri template lite Source Repository REPOSITORY
https://github.com/litejs/uri-template-lite
Uri template lite Source Repository REPOSITORY
https://github.com/litejs/uri-template-lite/commits/v22.9.0
research.jfrog.com/vulnerabilities/uri... WEB
https://research.jfrog.com/vulnerabilities/uri-template-lite-redos-xray-211351

Frequently Asked Questions

What is CVE-2021-43309?
CVE-2021-43309 is a security vulnerability in Uri template lite involving uri-template-lite Regular Expression Denial of Service under CWE-1333: Inefficient Regular Expression Complexity.
Which Uri template lite versions are affected?
Affected versions include releases prior to 22.9.0 across affected packages: uri-template-lite.
What version fixes CVE-2021-43309?
Upgrading to 22.9.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is uri-template-lite affected?
Yes, uri-template-lite is affected in releases prior to 22.9.0. Upgrade your dependency to 22.9.0 or later.
What is the CVSS score of CVE-2021-43309?
CVE-2021-43309 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-43309?
CVE-2021-43309 is classified under CWE-1333: Inefficient Regular Expression Complexity (The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.).
How can I check npm dependencies for CVE-2021-43309?
Run the dependency tree command: 'npm ls uri-template-lite'. 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-chw2-6c7r-37p7",
  "modified" : "2023-03-20T20:09:43Z",
  "published" : "2022-08-25T00:00:27Z",
  "aliases" : [ "CVE-2021-43309" ],
  "summary" : "uri-template-lite Regular Expression Denial of Service",
  "details" : "An exponential ReDoS (Regular Expression Denial of Service) can be triggered in the uri-template-lite npm package, when an attacker is able to supply arbitrary input to the \"URI.expand\" method.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "uri-template-lite"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "22.9.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-43309"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/litejs/uri-template-lite/commit/cbeec2b2a275d819fb534137a155df14729706f8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/litejs/uri-template-lite"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/litejs/uri-template-lite/commits/v22.9.0"
  }, {
    "type" : "WEB",
    "url" : "https://research.jfrog.com/vulnerabilities/uri-template-lite-redos-xray-211351"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1333", "CWE-697" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-09-01T22:21:35Z",
    "nvd_published_at" : "2022-08-24T16:15:00Z"
  }
}