How severe is CVE-2015-8857?

CVE-2015-8857 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2015-8857?

CVE-2015-8857 affects the following packages: uglify-js (npm), uglifier (RubyGems). Ecosystems affected: npm, RubyGems.

How do I fix CVE-2015-8857?

Update uglify-js to 2.4.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-8857 is resolved across your whole dependency graph.

How do I detect CVE-2015-8857 in my npm, RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for uglify-js. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2015-8857 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2015-8857?

O3 pinpoints whether CVE-2015-8857 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2015-8857 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2015-8857, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What type of vulnerability is CVE-2015-8857?

CVE-2015-8857 is classified as CWE-254 (CWE-254). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2015-8857 published, and has it been updated?

CVE-2015-8857 was published on January 23, 2017 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm💎 RubyGems

CVE-2015-8857

CRITICAL

Incorrect Handling of Non-Boolean Comparisons During Minification in uglify-js

Also known asGHSA-34r7-q49f-h37c

Published

Jan 23, 2017

Updated

Apr 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

1 known

Blast Radius

2 pkgs affected

📦uglify-js💎uglifier

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm, RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

The uglify-js package before 2.4.24 for Node.js does not properly account for non-boolean values when rewriting boolean expressions, which might allow attackers to bypass security mechanisms or possibly have unspecified other impact by leveraging improperly rewritten Javascript.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`uglify-js`	all versions	2.4.24
💎RubyGems	`uglifier`	all versions	2.7.2

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

The uglify-js package before 2.4.24 for Node.js does not properly accoun…

nodesecurity.ioNVDDec 2019

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for uglify-js. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update uglify-js to 2.4.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-8857 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2015-8857 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2015-8857. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2015-8857 in your dependencies?

O3 detects CVE-2015-8857 across npm, RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works