CVE-2026-42033: Axios Prototype Pollution Allows Response Tampering, HTTP Hijacking
The National Vulnerability Database has detailed CVE-2026-42033, a high-severity prototype pollution vulnerability affecting Axios, a popular promise-based HTTP client for browser and Node.js environments. This flaw, rated 7.4 CVSS, allows attackers to either silently intercept and modify JSON responses or completely hijack the underlying HTTP transport layer. This grants access to sensitive request credentials, headers, and body content.
The critical precondition for exploitation is existing prototype pollution from a separate co-dependency within the same process. This means the vulnerability isn’t standalone; it chains with another flaw. Axios versions prior to 1.15.1 and 0.31.1 are affected. The core issue lies in Axios reading specific keys without proper hasOwnProperty guards, making it susceptible when Object.prototype has been polluted.
This isn’t just about data modification; it’s about full control over the communication channel. For defenders, this means a compromised dependency in your stack could lead to a complete compromise of your application’s network interactions. Patching Axios is non-negotiable, but a deeper dive into your dependency tree for other prototype pollution vectors is also crucial. Attackers will always look for these chained vulnerabilities to maximize impact, and this one offers significant leverage once the initial condition is met.
What This Means For You
- If your application uses Axios, especially in environments where third-party dependencies are common, you need to immediately verify your Axios version. Upgrade to 1.15.1 or 0.31.1 to mitigate CVE-2026-42033. Beyond patching, audit your entire dependency chain for any other potential prototype pollution vulnerabilities that could serve as the prerequisite for this attack. This isn't theoretical; it's a direct path to data exfiltration and credential theft.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-42033: Axios Prototype Pollution - Suspicious JSON Response Modification
title: CVE-2026-42033: Axios Prototype Pollution - Suspicious JSON Response Modification
id: scw-2026-04-24-ai-1
status: experimental
level: high
description: |
This rule detects potential exploitation of CVE-2026-42033 by looking for web server responses to requests containing '__proto__' or 'constructor' in the query string. This pattern is indicative of an attempt to pollute the Object.prototype via the Axios library, which can lead to silent interception and modification of JSON responses. This is a critical indicator of the vulnerability being exploited for response tampering.
author: SCW Feed Engine (AI-generated)
date: 2026-04-24
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-42033/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
sc-status|startswith:
- '2'
cs-uri-query|contains:
- '__proto__'
- 'constructor'
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-42033 | Information Disclosure | Axios versions prior to 1.15.1 |
| CVE-2026-42033 | Information Disclosure | Axios versions prior to 0.31.1 |
| CVE-2026-42033 | Auth Bypass | Axios vulnerable to prototype pollution leading to HTTP transport hijacking |
| CVE-2026-42033 | Information Disclosure | Axios vulnerable to prototype pollution leading to interception and modification of JSON responses |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | April 24, 2026 at 21:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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