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Mallory
HighPublic exploit

Denial of Service in Axios mergeConfig via __proto__ config object

IdentifiersCVE-2026-25639CWE-1321

Axios contains a denial-of-service vulnerability in the mergeConfig function prior to versions 0.30.3 and 1.13.5. When mergeConfig processes a configuration object that has proto as an own property, such as an object produced from attacker-controlled JSON via JSON.parse(), it can throw a TypeError and crash the application. The issue arises during merging of configuration objects supplied to Axios request/config APIs. In affected deployments, an attacker can supply a crafted object like {"proto":{"x":1}} that is later passed into Axios configuration handling, causing the Node.js process to terminate.

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ANALYST BRIEF

Impact, mitigation & remediation

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Impact

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Successful exploitation causes complete denial of service of the affected application process. In practical terms, a single crafted request may crash a public-facing Node.js service that accepts untrusted input and feeds it into Axios configuration merging, taking the service offline until it is restarted. No confidentiality or integrity impact is described in the provided content; the primary impact is availability loss.

Mitigation

If you can’t patch tonight, do this now.

Do not pass untrusted or user-controlled objects directly into Axios request/config APIs. If user input must influence Axios options, map it into a new safe configuration object using a strict allowlist of supported keys. Explicitly reject or sanitize dangerous property names including proto, prototype, and constructor before merging. As an interim workaround, deep-clone into a null-prototype object such as Object.create(null) while filtering unsafe keys.

Remediation

Patch, then assume compromise.

Upgrade Axios to a fixed release. The provided content states the vulnerability is fixed in versions 0.30.3 and 1.13.5. Upgrade to 1.13.5 or later on the 1.x branch, or 0.30.3 or later on the 0.x branch, as applicable.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

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EXPOSURE SURFACE

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AxiosAxiosapplication

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Social activity13

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