---
id: "CVE-2026-118257"
kind: "vulnerability"
aliases: ["CVE-2026-118257", "GHSA-83rm-6c8r-g728"]
title: "Vue I18n: escapeParameter does not prevent XSS through srcdoc in translation messages"
severity: "high"
cvss: 7.2
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "vue-i18n", "fixed": [], "affected": "= 9.14.5", "ecosystem": "npm"}, {"name": "vue-i18n", "fixed": [], "affected": "= 10.0.8", "ecosystem": "npm"}, {"name": "vue-i18n", "fixed": ["11.4.14"], "affected": ">= 11.1.10, < 11.4.14", "ecosystem": "npm"}, {"name": "vue-i18n", "fixed": ["12.0.0-alpha.5"], "affected": "= 12.0.0-alpha.4", "ecosystem": "npm"}, {"name": "petite-vue-i18n", "fixed": [], "affected": "= 9.14.5", "ecosystem": "npm"}, {"name": "petite-vue-i18n", "fixed": [], "affected": "= 10.0.8", "ecosystem": "npm"}, {"name": "petite-vue-i18n", "fixed": ["11.4.14"], "affected": ">= 11.1.10, < 11.4.14", "ecosystem": "npm"}, {"name": "petite-vue-i18n", "fixed": ["12.0.0-alpha.5"], "affected": "= 12.0.0-alpha.4", "ecosystem": "npm"}, {"name": "@intlify/core-base", "fixed": [], "affected": "= 9.14.5", "ecosystem": "npm"}, {"name": "@intlify/core-base", "fixed": [], "affected": "= 10.0.8", "ecosystem": "npm"}, {"name": "@intlify/core-base", "fixed": ["11.4.14"], "affected": ">= 11.1.10, < 11.4.14", "ecosystem": "npm"}, {"name": "@intlify/core-base", "fixed": ["12.0.0-alpha.5"], "affected": "= 12.0.0-alpha.4", "ecosystem": "npm"}, {"name": "@intlify/core", "fixed": [], "affected": "= 9.14.5", "ecosystem": "npm"}, {"name": "@intlify/core", "fixed": [], "affected": "= 10.0.8", "ecosystem": "npm"}, {"name": "@intlify/core", "fixed": ["11.4.14"], "affected": ">= 11.1.10, < 11.4.14", "ecosystem": "npm"}, {"name": "@intlify/core", "fixed": ["12.0.0-alpha.5"], "affected": "= 12.0.0-alpha.4", "ecosystem": "npm"}, {"name": "@intlify/vue-i18n-core", "fixed": [], "affected": "= 9.14.5", "ecosystem": "npm"}, {"name": "@intlify/vue-i18n-core", "fixed": [], "affected": "= 10.0.8", "ecosystem": "npm"}, {"name": "@intlify/vue-i18n-core", "fixed": ["11.4.14"], "affected": ">= 11.1.10, < 11.4.14", "ecosystem": "npm"}, {"name": "@intlify/vue-i18n-core", "fixed": ["12.0.0-alpha.5"], "affected": "= 12.0.0-alpha.4", "ecosystem": "npm"}, {"name": "@intlify/shared", "fixed": [], "affected": "= 9.14.5", "ecosystem": "npm"}, {"name": "@intlify/shared", "fixed": [], "affected": "= 10.0.8", "ecosystem": "npm"}, {"name": "@intlify/shared", "fixed": ["11.4.14"], "affected": ">= 11.1.10, < 11.4.14", "ecosystem": "npm"}, {"name": "@intlify/shared", "fixed": ["12.0.0-alpha.5"], "affected": "= 12.0.0-alpha.4", "ecosystem": "npm"}]
ecosystems: ["npm"]
tags: ["cwe-116", "cwe-79", "frontend", "javascript", "node", "package", "vue", "vue-i18n"]
not_affected_if: ["escapeparameter-off", "i18n-t-only", "no-v-html"]
published_at: "2026-10-28T19:17:30+00:00"
first_seen_at: "2026-10-28T19:34:55+00:00"
updated_at: "2026-10-28T21:07:44+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118257", "first_seen_at": "2026-10-28T19:34:55+00:00"}, {"source": "ghsa", "url": "https://github.com/advisories/GHSA-83rm-6c8r-g728", "first_seen_at": "2026-10-28T21:07:44+00:00"}]
---

# Vue I18n: escapeParameter does not prevent XSS through srcdoc in translation messages

Vue I18n's sanitizeTranslatedHtml() escapes markup inside an iframe srcdoc value but leaves the srcdoc attribute active, so browsers parse the value as a same-origin nested document. An attacker who controls translation content or parameters can run script in the page when the app uses escapeParameter and renders translations with v-html.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- npm:vue-i18n affected = 9.14.5 fixed ?
- npm:vue-i18n affected = 10.0.8 fixed ?
- npm:vue-i18n affected >= 11.1.10, < 11.4.14 fixed 11.4.14
- npm:vue-i18n affected = 12.0.0-alpha.4 fixed 12.0.0-alpha.5
- npm:petite-vue-i18n affected = 9.14.5 fixed ?
- npm:petite-vue-i18n affected = 10.0.8 fixed ?
- npm:petite-vue-i18n affected >= 11.1.10, < 11.4.14 fixed 11.4.14
- npm:petite-vue-i18n affected = 12.0.0-alpha.4 fixed 12.0.0-alpha.5
- npm:@intlify/core-base affected = 9.14.5 fixed ?
- npm:@intlify/core-base affected = 10.0.8 fixed ?
- npm:@intlify/core-base affected >= 11.1.10, < 11.4.14 fixed 11.4.14
- npm:@intlify/core-base affected = 12.0.0-alpha.4 fixed 12.0.0-alpha.5
- npm:@intlify/core affected = 9.14.5 fixed ?
- npm:@intlify/core affected = 10.0.8 fixed ?
- npm:@intlify/core affected >= 11.1.10, < 11.4.14 fixed 11.4.14
- npm:@intlify/core affected = 12.0.0-alpha.4 fixed 12.0.0-alpha.5
- npm:@intlify/vue-i18n-core affected = 9.14.5 fixed ?
- npm:@intlify/vue-i18n-core affected = 10.0.8 fixed ?
- npm:@intlify/vue-i18n-core affected >= 11.1.10, < 11.4.14 fixed 11.4.14
- npm:@intlify/vue-i18n-core affected = 12.0.0-alpha.4 fixed 12.0.0-alpha.5
- npm:@intlify/shared affected = 9.14.5 fixed ?
- npm:@intlify/shared affected = 10.0.8 fixed ?
- npm:@intlify/shared affected >= 11.1.10, < 11.4.14 fixed 11.4.14
- npm:@intlify/shared affected = 12.0.0-alpha.4 fixed 12.0.0-alpha.5

## How to check

- Check the installed `vue-i18n` version in package.json and the lockfile; affected ranges are 11.1.10 to before 11.4.14, 12.0.0-alpha.4 to before 12.0.0-alpha.5, and 9.14.5, 10.0.8 and earlier (unsupported)
- Search the codebase for `escapeParameter` and for `v-html` used on translated strings (`$t`, `t(`)

## Fix

- Upgrade `vue-i18n` to `11.4.14` or later on the 11.x line, or to `12.0.0-alpha.5` or later on the 12.x alpha line
- Versions 9.x and 10.x are no longer supported; move to a supported line
- Until upgraded, stop rendering translated strings with v-html when escapeParameter is enabled

## Timeline

- 2026-10-28T19:34:55+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-118257
- 2026-10-28T21:07:44+00:00 ghsa https://github.com/advisories/GHSA-83rm-6c8r-g728

## From the sources

### Summary

When `escapeParameter` is enabled (`escapeParameterHtml` in the Legacy API), Vue I18n passes the translated string through `sanitizeTranslatedHtml()`. The sanitizer escapes `<` and `>` in attribute values and neutralizes event handler attributes such as `onerror`, but it does not handle the `srcdoc` attribute of `<iframe>`.

The value of `srcdoc` is an HTML document: the browser decodes the character references in it and parses the result as a nested document in the same origin. The escaping and the neutralization done by the sanitizer are both character references, so they are undone inside `srcdoc`. This bypasses the fix for CVE-2025-53892 (GHSA-x8qp-wqqm-57ph).

### Details

`sanitizeTranslatedHtml()` ([`packages/shared/src/sanitize.ts` in v11.4.13](https://github.com/intlify/vue-i18n/blob/v11.4.13/packages/shared/src/sanitize.ts#L126-L162)) works on the final translated string:

1. It escapes `<`, `>`, `"` and `'` inside quoted attribute values.
2. It rewrites the `on` of event handler attributes to `&#111;n`.
3. It replaces `javascript:` URLs in `href`, `src`, `action` and `formaction` with `about:blank`.

Inside `srcdoc`, steps 1 and 2 only produce character references, which the browser decodes before parsing the value as a document. Markup inside `srcdoc` therefore survives the sanitizer, with escaping or without it.

This can be reached in three ways:

- **A parameter inside `srcdoc`.** With a message such as `<iframe srcdoc="{content}"></iframe>`, `escapeParameter` escapes `content` into character references, and the browser decodes them again.
- **Markup in a message.** A message that contains an `<iframe srcdoc="...">` keeps it after sanitizing. The documentation asks not to use HTML messages with content from users, but it also says that the sanitizer neutralizes event handlers in the final HTML.
- **Together with GHSA-8rc2-428q-7ww3.** When a call passes a list and named values, the named values are not escaped. An `<iframe srcdoc="...">` in a named value then reaches the sanitizer as markup, even with an ordinary message such as `{0} {name}`.

### PoC

```js
import { createI18n } from 'vue-i18n'

const i18n = createI18n({
  legacy: false,
  locale: 'en',
  escapeParameter: true,
  messages: {
    en: { message: '<iframe srcdoc="<b>x</b>"></iframe>' }
  }
})

console.log(i18n.global.t('message'))
// v11.4.13: <iframe srcdoc="&lt;b&gt;x&lt;/b&gt;"></iframe>
```

The browser decodes the value and renders `<b>x</b>` as a separate document inside the `<iframe>`, in the same origin as the page. Any markup in that position is parsed the same way.

### Impact

Applications are affected when they enable `escapeParameter`, render translations as HTML (for example with `v-html`), and one of the following applies:

- an untrusted value is passed as a parameter that the message places inside `srcdoc`,
- message content is not fully trusted (for example crowdsourced or stored translations), or
- untrusted named values are passed in the same call as a list (GHSA-8rc2-428q-7ww3).

An attacker can then run script in the origin of the application (DOM-based XSS), despite the sanitizer.

Rendering through `<i18n-t>` is not affected, since it does not render translations as HTML.

### Patches

Fixed in 11.4.14 and 12.0.0-alpha.5. The sanitizer now neutralizes the `srcdoc` attribute itself, in the same way as event handler attributes.

v9 and v10 are no longer supported and will not be fixed. Please migrate to v11.

### Workarounds

- Do not render translations that can contain untrusted content with `v-html`. Use component interpolation (`<i18n-t>`) instead.
- Do not put `srcdoc` in translation messages, and do not pass values into it.

### References

- [CWE-79](https://cwe.mitre.org/data/definitions/79.html), [CWE-116](https://cwe.mitre.org/data/definitions/116.html)
- [GHSA-x8qp-wqqm-57ph](https://github.com/intlify/vue-i18n/security/advisories/GHSA-x8qp-wqqm-57ph) (CVE-2025-53892): the fix that added `sanitizeTranslatedHtml()`
- [GHSA-8rc2-428q-7ww3](https://github.com/intlify/vue-i18n/security/advisories/GHSA-8rc2-428q-7ww3): named values are not escaped when a list is also passed
- [HTML Standard: the `srcdoc` attribute](https://html.spec.whatwg.org/multipage/iframe-embed-object.html#attr-iframe-srcdoc)

---

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