Critical Axios Vulnerability Lets Attackers Remotely Execute Code

Key Takeaways

• A critical vulnerability, CVE-2026-40175, has been discovered in Axios, a widely used HTTP client.
• The flaw allows attackers to achieve remote code execution and compromise cloud environments without direct user interaction.
• All Axios versions prior to 1.15.0 are affected, including v0.x and v1.x releases.
• A patch is available in Axios version 1.15.0 and later, which introduces enhanced header validation.

The cybersecurity community is on high alert following the disclosure of a severe security vulnerability in Axios, a popular promise-based HTTP client for Node.js and web browsers. This critical flaw could enable attackers to remotely execute code and potentially compromise entire cloud environments.

Security researcher Jason Saayman recently unveiled details of this unrestricted vulnerability, which facilitates the exfiltration of cloud metadata.

What makes this flaw particularly dangerous is its ability to allow threat actors to achieve remote code execution or a complete cloud environment compromise without requiring any direct user input.

Axios Vulnerability Details and Proof of Concept

The vulnerability, identified as CVE-2026-40175, is rooted in Axios’s header processing component, specifically within the lib/adapters/http.js file. The core issue stems from Axios’s lack of proper HTTP header sanitization, which leads to destructive behavior when prototype pollution occurs in a third-party dependency.

If an attacker successfully pollutes the Object.prototype via an unrelated library within the software stack, Axios inadvertently merges these malicious properties during its standard configuration process. Since the software fails to sanitize these merged header values for carriage return and line feed characters, the polluted property transforms into a stealthy request-smuggling payload.

This attack chain is exceptionally severe because it requires no direct user interaction. A seemingly safe, hardcoded request programmed by a developer can be unknowingly hijacked to trigger the full exploit.

When a smuggled secondary request successfully executes, it can directly target the AWS Metadata Service. This sophisticated exploit circumvents AWS IMDSv2 security controls by injecting the necessary session token headers—an action that typical server-side request forgery attacks cannot achieve.

Once the metadata service returns a valid session token, attackers can easily steal IAM credentials. This unauthorized access grants threat actors the ability to rapidly escalate privileges, pivot into restricted internal administrative panels via cookie or authorization header injection, and ultimately achieve a complete cloud account takeover.

This critical flaw impacts numerous applications across the global development ecosystem. Vulnerable software releases include all versions prior to 1.15.0 (encompassing v0.x and v1.x). The fully patched releases are version 1.15.0 and newer.

What You Should Do

• Upgrade Immediately: Development and security teams must urgently upgrade their Axios installations to version 1.15.0 or later to fully mitigate this critical vulnerability. This release introduces strict header validation mechanisms, which ensure that any header values containing invalid characters will immediately trigger a critical security error before processing.
• Audit Dependencies: Organizations should comprehensively audit their complete dependency graphs for underlying prototype pollution vulnerabilities in other npm packages. Since Axios leverages these helper flaws to execute the exploit, securing the entire software stack is essential for maintaining robust security.

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