Axios, a widely used promise‑based HTTP client, has a prototype‑pollution vulnerability that allows an attacker to inject unsanitized header values into outbound requests. The flaw can be exploited through a chain of malicious third‑party dependencies, enabling data to be sent from a cloud environment via unsanitized headers. This vulnerability is a form of cloud metadata exfiltration and could expose sensitive information such as instance metadata or credentials that are only available within the cloud environment. It ends up affecting confidentiality by allowing attackers to read data that is meant to remain internal to the cloud platform.

All versions of Axios before v1.15.0 for Node.js and before v0.3.1 for browsers are affected. These versions are vulnerable to the header injection chain. Updating to v1.15.0 or v0.3.1 removes the vulnerable code paths and prevents the prototype‑pollution chain from executing.

The CVSS score of 4.8 indicates the flaw is moderately severe, and its EPSS score of less than 1% suggests that exploitation is currently uncommon. The vulnerability is not listed in the CISA KEV catalog. The attack vector likely involves inserting malicious code into a third‑party dependency that is pulled into an Axios request. Once the chain is triggered, the attacker can supply arbitrary header names and values, allowing data to be sent to external endpoints or pulled from the cloud metadata service.