What Happened

Axios, a widely-used promise based HTTP client for the browser and Node.js, has a critical vulnerability labeled CVE-2026-40175. This flaw affects versions prior to 1.15.0 and has been assigned a CVSS score of 10, indicating its critical nature. The vulnerability allows an attacker to escalate a Prototype Pollution flaw in any third-party dependency into Remote Code Execution (RCE) or a Full Cloud Compromise through an AWS IMDSv2 bypass.

The issue was identified in the core mechanism of Axios, where its handling of nested object structures in JavaScript could be exploited via a "Gadget" attack chain. This attack chain is particularly dangerous when present in environments leveraging AWS, where it can be used to bypass AWS Identity and Access Management (IAM) controls, leading to total environment exposure.

Technical Details

The vulnerability arises from the way Axios processes HTTP requests that can include nested objects, which, when manipulated correctly, can result in Prototype Pollution. Prototype Pollution is a form of attack where an object's prototype (or globally used features) is altered, providing a mechanism for the execution of unauthorized code.

Exploiting this vulnerability requires leveraging a vulnerable third-party dependency that Axios interfaces with. Using a crafted payload, an attacker exploits this dependency, initially causing Prototype Pollution. This step acts as a foothold for further exploitation, culminating in Remote Code Execution or full compromise of cloud infrastructure through AWS IMDSv2.

The conditions for exploiting this vulnerability necessitate application logic that allows free-form user inputs handled by Axios, a reachable vulnerability in the application's dependency tree for Prototype Pollution, and a reliance on AWS for environment management. Indicators of Compromise (IOCs) include unexpected HTTP requests with highly structured object payloads and increased access attempts to metadata services on AWS instances.

Impact

This vulnerability has a far-reaching impact affecting any application that utilizes Axios versions prior to 1.15.0, particularly those running on cloud infrastructure like AWS. Since the flaw can lead to RCE, attackers could gain complete control over affected systems, execute arbitrary code, and exfiltrate sensitive data.

Organizations using vulnerable Axios versions in their applications, especially those that integrate cloud services, are at highest risk. The potential for full cloud environment compromise underscores the criticality of this vulnerability, demanding immediate attention from affected entities.

What To Do

  • Immediate Upgrade: Upgrade to Axios version 1.15.0 or later. This version includes patches to neutralize the Gadget attack chain and mitigate Prototype Pollution risks.
  • Dependency Review: Conduct a thorough review of all third-party dependencies in use to identify any that may also include Prototype Pollution vulnerabilities.
  • Network Monitoring: Implement network monitoring and logging to detect unusual patterns indicative of exploitation attempts, especially focusing on HTTP traffic patterns.
  • IAM Hardening: Reinforce AWS IAM roles and permissions, incorporating the principle of least privilege to limit the potential impact of a compromised environment.

By executing these steps, organizations can mitigate the risks posed by CVE-2026-40175 effectively. Staying vigilant with software updates and maintaining stringent security protocols are key strategies in protecting systems from similar vulnerabilities in the future.