{"id":"GHSA-83rm-6c8r-g728","summary":"Vue I18n: escapeParameter does not prevent XSS through srcdoc in translation messages","details":"### Summary\n\nWhen `escapeParameter` is enabled (`escapeParameterHtml` in the Legacy API), Vue I18n passes the translated string through `sanitizeTranslatedHtml()`. The sanitizer escapes `\u003c` and `\u003e` in attribute values and neutralizes event handler attributes such as `onerror`, but it does not handle the `srcdoc` attribute of `\u003ciframe\u003e`.\n\nThe 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).\n\n### Details\n\n`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:\n\n1. It escapes `\u003c`, `\u003e`, `\"` and `'` inside quoted attribute values.\n2. It rewrites the `on` of event handler attributes to `on`.\n3. It replaces `javascript:` URLs in `href`, `src`, `action` and `formaction` with `about:blank`.\n\nInside `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.\n\nThis can be reached in three ways:\n\n- **A parameter inside `srcdoc`.** With a message such as `\u003ciframe srcdoc=\"{content}\"\u003e\u003c/iframe\u003e`, `escapeParameter` escapes `content` into character references, and the browser decodes them again.\n- **Markup in a message.** A message that contains an `\u003ciframe srcdoc=\"...\"\u003e` 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.\n- **Together with GHSA-8rc2-428q-7ww3.** When a call passes a list and named values, the named values are not escaped. An `\u003ciframe srcdoc=\"...\"\u003e` in a named value then reaches the sanitizer as markup, even with an ordinary message such as `{0} {name}`.\n\n### PoC\n\n```js\nimport { createI18n } from 'vue-i18n'\n\nconst i18n = createI18n({\n  legacy: false,\n  locale: 'en',\n  escapeParameter: true,\n  messages: {\n    en: { message: '\u003ciframe srcdoc=\"\u003cb\u003ex\u003c/b\u003e\"\u003e\u003c/iframe\u003e' }\n  }\n})\n\nconsole.log(i18n.global.t('message'))\n// v11.4.13: \u003ciframe srcdoc=\"<b>x</b>\"\u003e\u003c/iframe\u003e\n```\n\nThe browser decodes the value and renders `\u003cb\u003ex\u003c/b\u003e` as a separate document inside the `\u003ciframe\u003e`, in the same origin as the page. Any markup in that position is parsed the same way.\n\n### Impact\n\nApplications are affected when they enable `escapeParameter`, render translations as HTML (for example with `v-html`), and one of the following applies:\n\n- an untrusted value is passed as a parameter that the message places inside `srcdoc`,\n- message content is not fully trusted (for example crowdsourced or stored translations), or\n- untrusted named values are passed in the same call as a list (GHSA-8rc2-428q-7ww3).\n\nAn attacker can then run script in the origin of the application (DOM-based XSS), despite the sanitizer.\n\nRendering through `\u003ci18n-t\u003e` is not affected, since it does not render translations as HTML.\n\n### Patches\n\nFixed 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.\n\nv9 and v10 are no longer supported and will not be fixed. Please migrate to v11.\n\n### Workarounds\n\n- Do not render translations that can contain untrusted content with `v-html`. Use component interpolation (`\u003ci18n-t\u003e`) instead.\n- Do not put `srcdoc` in translation messages, and do not pass values into it.\n\n### References\n\n- [CWE-79](https://cwe.mitre.org/data/definitions/79.html), [CWE-116](https://cwe.mitre.org/data/definitions/116.html)\n- [GHSA-x8qp-wqqm-57ph](https://github.com/intlify/vue-i18n/security/advisories/GHSA-x8qp-wqqm-57ph) (CVE-2025-53892): the fix that added `sanitizeTranslatedHtml()`\n- [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\n- [HTML Standard: the `srcdoc` attribute](https://html.spec.whatwg.org/multipage/iframe-embed-object.html#attr-iframe-srcdoc)","aliases":["CVE-2026-118257"],"modified":"2026-10-28T21:15:05.568930892Z","published":"2026-10-28T21:06:24Z","database_specific":{"nvd_published_at":null,"cwe_ids":["CWE-116","CWE-79"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-10-28T21:06:24Z"},"references":[{"type":"WEB","url":"https://github.com/intlify/vue-i18n/security/advisories/GHSA-83rm-6c8r-g728"},{"type":"WEB","url":"https://github.com/intlify/vue-i18n/pull/2679"},{"type":"WEB","url":"https://github.com/intlify/vue-i18n/commit/43391d20e7c85403cb59bdb21b5d542819f54042"},{"type":"PACKAGE","url":"https://github.com/intlify/vue-i18n"},{"type":"WEB","url":"https://github.com/intlify/vue-i18n/releases/tag/v11.4.14"},{"type":"WEB","url":"https://github.com/intlify/vue-i18n/releases/tag/v12.0.0-alpha.5"}],"affected":[{"package":{"name":"vue-i18n","ecosystem":"npm","purl":"pkg:npm/vue-i18n"},"versions":["9.14.5"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"vue-i18n","ecosystem":"npm","purl":"pkg:npm/vue-i18n"},"versions":["10.0.8"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"vue-i18n","ecosystem":"npm","purl":"pkg:npm/vue-i18n"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.1.10"},{"fixed":"11.4.14"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"vue-i18n","ecosystem":"npm","purl":"pkg:npm/vue-i18n"},"ranges":[{"type":"SEMVER","events":[{"introduced":"12.0.0-alpha.4"},{"fixed":"12.0.0-alpha.5"}]}],"versions":["12.0.0-alpha.4"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"petite-vue-i18n","ecosystem":"npm","purl":"pkg:npm/petite-vue-i18n"},"versions":["9.14.5"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"petite-vue-i18n","ecosystem":"npm","purl":"pkg:npm/petite-vue-i18n"},"versions":["10.0.8"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"petite-vue-i18n","ecosystem":"npm","purl":"pkg:npm/petite-vue-i18n"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.1.10"},{"fixed":"11.4.14"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"petite-vue-i18n","ecosystem":"npm","purl":"pkg:npm/petite-vue-i18n"},"ranges":[{"type":"SEMVER","events":[{"introduced":"12.0.0-alpha.4"},{"fixed":"12.0.0-alpha.5"}]}],"versions":["12.0.0-alpha.4"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"@intlify/core-base","ecosystem":"npm","purl":"pkg:npm/%40intlify/core-base"},"versions":["9.14.5"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"@intlify/core-base","ecosystem":"npm","purl":"pkg:npm/%40intlify/core-base"},"versions":["10.0.8"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"@intlify/core-base","ecosystem":"npm","purl":"pkg:npm/%40intlify/core-base"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.1.10"},{"fixed":"11.4.14"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"@intlify/core-base","ecosystem":"npm","purl":"pkg:npm/%40intlify/core-base"},"ranges":[{"type":"SEMVER","events":[{"introduced":"12.0.0-alpha.4"},{"fixed":"12.0.0-alpha.5"}]}],"versions":["12.0.0-alpha.4"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g728.json"}},{"package":{"name":"@intlify/core","ecosystem":"npm","purl":"pkg:npm/%40intlify/core"},"versions":["9.14.5"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-83rm-6c8r-g728/GHSA-83rm-6c8r-g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