{"id":"CVE-2026-54705","aliases":["GHSA-fm7p-gw32-828p"],"url":"https://o3.security/vulnerability/CVE-2026-54705","summary":"mathlive's Lack of Escaping of HTML allows for XSS","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 (`<`, `>`, `&`, `\"`) 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.\n\nBoth 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`).\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('math-span');\ns.style.display = 'block';\ns.textContent = '\\\\text{<img src=x onerror=alert(1)>}';\ndocument.body.appendChild(s);\ns.scrollIntoView();\n```\n\nEquivalent payloads: `\\mbox{<img src=x onerror=alert(1)>}`\n\nor\n\n```js\nimport { convertLatexToMarkup } from 'mathlive';\ndocument.body.innerHTML = convertLatexToMarkup('\\\\text{<img src=x onerror=alert(1)>}');\n```\n\n### Impact\n\nMathLive users who render untrusted mathematical expressions can encounter malicious input that runs arbitrary JavaScript.","published":"2026-07-29T17:21:20.414Z","modified":"2026-10-28T02:30:29.965017831Z","cvss":{"score":6.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"},"epss":{"score":0.00208,"percentile":0.11171,"asOf":"2026-09-15"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"mathlive","fixedVersion":"0.110.0"}],"fix":{"url":"https://github.com/arnog/mathlive/commit/5fe1c46153883f9ec0249a5c8c34e64aaae9cfb8","label":"arnog/mathlive@5fe1c46"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54705.json"},{"type":"ADVISORY","url":"https://github.com/arnog/mathlive/security/advisories/GHSA-fm7p-gw32-828p"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54705"},{"type":"REPORT","url":"https://github.com/arnog/mathlive/issues/3028"},{"type":"FIX","url":"https://github.com/arnog/mathlive/commit/5fe1c46153883f9ec0249a5c8c34e64aaae9cfb8"},{"type":"PACKAGE","url":"https://github.com/arnog/mathlive"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:30:29.965017831Z"}}