CVE-2026-44494: Axios: Full Man-in-the-Middle via Prototype Pollution Gadget in `config.proxy`

Synopsis

A prototype pollution gadget vulnerability in the Axios HTTP client library (versions 1.0.0 through before 1.16.0) allows an attacker to escalate any existing prototype pollution in the application's dependency tree into a full man-in-the-middle (MITM) attack. The vulnerability is reachable over the network with no authentication required, and the attack targets the config.proxy property resolution path in Axios's HTTP adapter. Successful exploitation gives an attacker full read and write access to all HTTP traffic the affected application sends, including authentication credentials. HarborGuard tracks this advisory and will make a patched-image rebuild available the moment an upstream fix version is published.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The vulnerability is exploited over the network; the attacker must be able to deliver prototype pollution into the target application's runtime and have network-level visibility to act as a proxy endpoint.

• AuthenticationNot required

  No credentials or account are needed; the attacker does not need to authenticate to the target service to exploit this vulnerability.

• Victim interactionNot required

  No user action is required; exploitation occurs entirely within the server-side Node.js process when Axios resolves config.proxy through the prototype chain.

• Attack complexityDetail

  Attack complexity is rated High because exploitation requires a pre-existing prototype pollution condition elsewhere in the dependency tree, plus timing or positioning to intercept traffic, rather than a single self-contained step.

Blast Radius

• The attacker intercepts all outbound HTTP requests made by the affected application, reading authentication tokens, API keys, and session credentials in transit.
• The attacker modifies HTTP request and response bodies in flight, allowing injection of malicious payloads into data the application trusts and acts on.
• Any downstream service the application communicates with is reachable through the forged proxy, expanding the attacker's foothold beyond the initially compromised process.