{"id":"CVE-2024-28244","aliases":["GHSA-cvr6-37gx-v8wc"],"url":"https://o3.security/vulnerability/CVE-2024-28244","summary":"KaTeX's maxExpand bypassed by Unicode sub/superscripts","details":"### Impact\nKaTeX users who render untrusted mathematical expressions could encounter malicious input using `\\def` or `\\newcommand` that causes a near-infinite loop, despite setting `maxExpand` to avoid such loops. This can be used as an availability attack, where e.g. a client rendering another user's KaTeX input will be unable to use the site due to memory overflow, tying up the main thread, or stack overflow.\n\n### Patches\nUpgrade to KaTeX v0.16.10 to remove this vulnerability.\n\n### Workarounds\nForbid inputs containing any of the characters `₊₋₌₍₎₀₁₂₃₄₅₆₇₈₉ₐₑₕᵢⱼₖₗₘₙₒₚᵣₛₜᵤᵥₓᵦᵧᵨᵩᵪ⁺⁻⁼⁽⁾⁰¹²³⁴⁵⁶⁷⁸⁹ᵃᵇᶜᵈᵉᵍʰⁱʲᵏˡᵐⁿᵒᵖʳˢᵗᵘʷˣʸᶻᵛᵝᵞᵟᵠᵡ` before passing them to KaTeX.\n(There is no easy workaround for the auto-render extension.)\n\n### Details\nKaTeX supports an option named `maxExpand` which aims to prevent infinitely recursive macros from consuming all available memory and/or triggering a stack overflow error. Unfortunately, [support for \"Unicode (sub|super)script characters\"](https://github.com/KaTeX/KaTeX/commit/d8fc35e6a97f8e561c723b93ad275cf5a7f3094a) allows an attacker to bypass this limit. Each sub/superscript group instantiated a separate Parser with its own limit on macro executions, without inheriting the current count of macro executions from its parent. This has been corrected in KaTeX v0.16.10.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue or security advisory in the [KaTeX repository](https://github.com/KaTeX/KaTeX/)\n* Email us at [katex-security@mit.edu](mailto:katex-security@mit.edu)","published":"2024-03-25T19:45:50.907Z","modified":"2026-10-28T02:30:26.211345284Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.02155,"percentile":0.81286,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"katex","fixedVersion":"0.16.10"}],"fix":{"url":"https://github.com/KaTeX/KaTeX/commit/085e21b5da05414efefa932570e7201a7c70e5b2","label":"KaTeX/KaTeX@085e21b"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/28xxx/CVE-2024-28244.json"},{"type":"ADVISORY","url":"https://github.com/KaTeX/KaTeX/security/advisories/GHSA-cvr6-37gx-v8wc"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-28244"},{"type":"FIX","url":"https://github.com/KaTeX/KaTeX/commit/085e21b5da05414efefa932570e7201a7c70e5b2"},{"type":"PACKAGE","url":"https://github.com/KaTeX/KaTeX"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:30:26.211345284Z"}}