# CVE-2025-27597: Intlify Vue I18n prototype pollution in handleFlatJson

Source: https://junglewise.ai/threats/cve-2025-27597-intlify-vue-i18n-prototype-pollution-in-handleflatjson  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-03-07. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2025-27597 · Severity: high · CVSS 4 · Published 2025-03-07

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.

Technologies: [@intlify/core (npm)](https://junglewise.ai/threats/technologies/intlify-core), [@intlify/core-base (npm)](https://junglewise.ai/threats/technologies/intlify-core-base), [@intlify/vue-i18n-core (npm)](https://junglewise.ai/threats/technologies/intlify-vue-i18n-core), [petite-vue-i18n (npm)](https://junglewise.ai/threats/technologies/petite-vue-i18n), [vue-i18n (npm)](https://junglewise.ai/threats/technologies/vue-i18n). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2025-27597 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-27597 being exploited in the wild.

**How severe is CVE-2025-27597?** High severity, with a CVSS score of 4, published 7 March 2025.

**Which products and versions are affected?** @intlify/core (npm) SEMVER:introduced=9.1.0,fixed=9.1.11; @intlify/core-base (npm) SEMVER:introduced=9.1.0,fixed=9.1.11; @intlify/message-resolver (npm) SEMVER:introduced=9.1.0,fixed=9.1.11; @intlify/vue-i18n-core (npm) SEMVER:introduced=9.2.0,fixed=9.14.3; and 2 more.

**Is there a fix for CVE-2025-27597?** Yes. @intlify/core (npm): upgrade to 9.1.11 or later; @intlify/core-base (npm): upgrade to 9.1.11 or later; @intlify/message-resolver (npm): upgrade to 9.1.11 or later; @intlify/vue-i18n-core (npm): upgrade to 9.14.3 or later; petite-vue-i18n (npm): upgrade to 10.0.6 or later; vue-i18n (npm): upgrade to 9.14.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2025-27597 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2025-27597?** Check whether you run @intlify/core (npm), @intlify/core-base (npm), @intlify/message-resolver (npm) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- @intlify/core (npm): upgrade to 9.1.11 or later

  ```sh
  npm install @intlify/core@9.1.11
  ```

- @intlify/core-base (npm): upgrade to 9.1.11 or later

  ```sh
  npm install @intlify/core-base@9.1.11
  ```

- @intlify/message-resolver (npm): upgrade to 9.1.11 or later

  ```sh
  npm install @intlify/message-resolver@9.1.11
  ```

- @intlify/vue-i18n-core (npm): upgrade to 9.14.3 or later

  ```sh
  npm install @intlify/vue-i18n-core@9.14.3
  ```

- petite-vue-i18n (npm): upgrade to 10.0.6 or later

  ```sh
  npm install petite-vue-i18n@10.0.6
  ```

- vue-i18n (npm): upgrade to 9.14.3 or later

  ```sh
  npm install vue-i18n@9.14.3
  ```


## 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

## Identifiers

- CVE-2025-27597
- GHSA-p2ph-7g93-hw3m

## 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

## References

- [https://api.github.com/users/mestrtee](https://api.github.com/users/mestrtee)
- [https://github.com/mestrtee](https://github.com/mestrtee)
- [https://api.github.com/users/mestrtee/gists%7B/gist_id%7D](https://api.github.com/users/mestrtee/gists%7B/gist_id%7D)
- [https://api.github.com/users/mestrtee/repos](https://api.github.com/users/mestrtee/repos)
- [https://avatars.githubusercontent.com/u/162041574?v=4](https://avatars.githubusercontent.com/u/162041574?v=4)
- [https://api.github.com/users/mestrtee/events%7B/privacy%7D](https://api.github.com/users/mestrtee/events%7B/privacy%7D)

## Related threats

- [Vue I18n XSS in sanitizeTranslatedHtml srcdoc escaping](https://junglewise.ai/threats/cve-2026-118257-vue-i18n-is-the-internationalization-plugin-for-vue-js-from-11-1)
- [Vue I18n XSS in escapeParameter with named interpolation](https://junglewise.ai/threats/cve-2026-118256-vue-i18n-is-the-internationalization-plugin-for-vue-js-from-9-0)
- [vue-i18n escapeParameterHtml DOM-based XSS in tag attributes](https://junglewise.ai/threats/cve-2025-53892-vue-i18n-escapeparameterhtml-dom-based-xss-in-tag-attributes)
- [Intlify shared prototype pollution in deepCopy](https://junglewise.ai/threats/cve-2024-52810-intlify-shared-prototype-pollution-in-deepcopy)
- [vue-i18n cross-site scripting with prototype pollution](https://junglewise.ai/threats/cve-2024-52809-vue-i18n-cross-site-scripting-with-prototype-pollution)