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

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Vue I18n is the internationalization plugin for Vue.js. From 11.1.10 until 11.4.14 and from 12.0.0-alpha.4 until 12.0.0-alpha.5, sanitizeTranslatedHtml() escapes markup and event-handler text inside an iframe srcdoc value but leaves the srcdoc attribute active. Browsers decode the character references and parse the value as a same-origin nested HTML document, allowing attacker-controlled parameters or translation content placed in srcdoc to execute script when applications enable escapeParameter and render translations as HTML through v-html. Versions 9.14.5 and 10.0.8 are also affected and are no longer supported, while i18n-t rendering is not affected. This issue is fixed in versions 11.4.14 and 12.0.0-alpha.5.

Source published

28 Oct 2026 18:23:49 UTC

Source modified

29 Oct 2026 20:55:05 UTC

Observed here

29 Oct 2026 21:48:56 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Vue I18n is the internationalization plugin for Vue.js. From 11.1.10 until 11.4.14 and from 12.0.0-alpha.4 until 12.0.0-alpha.5, sanitizeTranslatedHtml() escapes markup and event-handler text inside an iframe srcdoc value but leaves the srcdoc attribute active. Browsers decode the character references and parse the value as a same-origin nested HTML document, allowing attacker-controlled parameters or translation content placed in srcdoc to execute script when applications enable escapeParameter and render translations as HTML through v-html. Versions 9.14.5 and 10.0.8 are also affected and are no longer supported, while i18n-t rendering is not affected. This issue is fixed in versions 11.4.14 and 12.0.0-alpha.5.

Source published

Oct 28, 2026, 6:23:49 PM (timezone not stated)

Source modified

Oct 29, 2026, 8:55:05 PM (timezone not stated)

Observed here

6 Nov 2026 00:45:09 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Vue I18n is the internationalization plugin for Vue.js. From 11.1.10 until 11.4.14 and from 12.0.0-alpha.4 until 12.0.0-alpha.5, sanitizeTranslatedHtml() escapes markup and event-handler text inside an iframe srcdoc value but leaves the srcdoc attribute active. Browsers decode the character references and parse the value as a same-origin nested HTML document, allowing attacker-controlled parameters or translation content placed in srcdoc to execute script when applications enable escapeParameter and render translations as HTML through v-html. Versions 9.14.5 and 10.0.8 are also affected and are no longer supported, while i18n-t rendering is not affected. This issue is fixed in versions 11.4.14 and 12.0.0-alpha.5.

Source published

28 Oct 2026 19:17:30 UTC

Source modified

29 Oct 2026 21:17:15 UTC

Observed here

30 Oct 2026 22:45:44 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

### 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)

Source published

28 Oct 2026 21:06:24 UTC

Source modified

28 Oct 2026 21:15:05 UTC

Observed here

28 Oct 2026 21:55:29 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Publisher rating · HIGH