Executive brief
Vue I18n is a popular internationalization library used in web applications to manage multi-language content. This vulnerability allows attackers to inject malicious properties into the core JavaScript object prototype through the `handleFlatJson` function. This can cause application crashes (denial of service) or, in worst-case scenarios where polluted properties interact with code execution functions like `eval` or `exec`, enable attackers to run arbitrary commands on the server or within the application.
Technical details
The vulnerability is a classic prototype pollution flaw in the `handleFlatJson` function across multiple Intlify packages (@intlify/message-resolver, @intlify/vue-i18n-core, vue-i18n, and others). The function inadequately sanitizes input object keys, allowing payloads containing `__proto__` or constructor properties to modify Object.prototype. Attack vectors include network-based exploitation if the vulnerable function processes untrusted user input (e.g., from API requests or configuration files). While the minimum impact is denial of service, the consequences can escalate depending on application context: if polluted prototype properties propagate to sensitive Node.js APIs (exec, eval, require), it may enable arbitrary code execution. No authentication or special privileges are required; patches are available (versions 9.1.11, 9.14.3, 10.0.6, and 11.1.2 or later).
Affected products
- Intlify @intlify/core >= 9.1.0, < 9.1.11
- Intlify @intlify/core-base >= 9.1.0, < 9.1.11
- Intlify @intlify/message-resolver >= 9.1.0, < 9.1.11
- Intlify @intlify/vue-i18n-core >= 9.2.0, < 9.14.3; >= 10.0.0-alpha.1, < 10.0.6; >= 11.0.0-beta.0, < 11.1.2
- Intlify vue-i18n >= 9.1.0, < 9.14.3; >= 10.0.0-alpha.1, < 10.0.6; >= 11.0.0-beta.0, < 11.1.2
- Intlify petite-vue-i18n >= 10.0.0, < 10.0.6; >= 11.0.0-beta.0, < 11.1.2
Timeline
- 2025-03-07: disclosed: Vulnerability disclosed via GitHub Advisory GHSA-p2ph-7g93-hw3m and CVE-2025-27597
- 2025-03-07: patched: Patches released: @intlify/core 9.1.11, @intlify/message-resolver 9.1.11, @intlify/core-base 9.1.11, @intlify/vue-i18n-core 9.14.3/10.0.6/11.1.2, vue-i18n 9.14.3/10.0.6/11.1.2, petite-vue-i18n 10.0.6/11.1.2