GHSA-rxrv-835q-v5mh — locutus
Fix: locutusjs/locutus@042af9cGHSA-rxrv-835q-v5mh is a CWE-1321 vulnerability in locutus. A fix is available for locutus — see the affected versions and patch details below.
locutus is vulnerable to Prototype Pollution
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-rxrv-835q-v5mh.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
locutusnpmDescription
Summary
A Prototype Pollution vulnerability exists in the the npm package locutus (>2.0.12). Despite a previous fix that attempted to mitigate Prototype Pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using String.prototype. This issue was fixed in version 2.0.39.
Details
The vulnerability resides in line 77 to 79 of https://github.com/locutusjs/locutus/blob/main/src/php/strings/parse_str.js where includes() function is used to check whether user provided input contain forbidden strings.
PoC
Steps to reproduce
- Install latest version of locutus using npm install or cloning from git
- Run the following code snippet:
String.prototype.includes = () => false;
console.log({}.polluted);
const locutus = require('locutus');
locutus.php.strings.parse_str('constructor[prototype][polluted]=yes');
console.log({}.polluted); // prints yes -> indicating that the patch was bypassed and Prototype Pollution occurred
Expected behavior
Prototype Pollution should be prevented and {} should not gain new properties. This should be printed on the console:
undefined
undefined OR throw an Error
Actual behavior
Object.prototype is polluted This is printed on the console:
undefined
yes
Impact
This is a Prototype Pollution vulnerability, which can have severe security implications depending on how locutus is used by downstream applications. Any application that processes attacker-controlled input using this locutus.php.strings.parse_str may be affected. It could potentially lead to the following problems:
- Authentication bypass
- Denial of service
- Remote code execution (if polluted property is passed to sinks like eval or child_process)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | locutus | ≥ 2.0.12&&< 2.0.39 | 2.0.39npm install locutus@2.0.39 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for locutus, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update locutus to 2.0.39 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rxrv-835q-v5mh 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-rxrv-835q-v5mh can be triaged on real exposure rather than presence alone.
Tailored to GHSA-rxrv-835q-v5mh. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-rxrv-835q-v5mh in your dependencies?
O3 Security finds GHSA-rxrv-835q-v5mh across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.