{"id":"GHSA-cvr6-37gx-v8wc","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)","aliases":["CVE-2024-28244"],"modified":"2026-09-10T03:50:10.288677780Z","published":"2024-03-25T19:38:29Z","database_specific":{"cwe_ids":["CWE-606","CWE-674"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2024-03-25T19:38:29Z","nvd_published_at":"2024-03-25T20:15:08Z"},"references":[{"type":"WEB","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":"WEB","url":"https://github.com/KaTeX/KaTeX/commit/085e21b5da05414efefa932570e7201a7c70e5b2"},{"type":"PACKAGE","url":"https://github.com/KaTeX/KaTeX"}],"affected":[{"package":{"name":"katex","ecosystem":"npm","purl":"pkg:npm/katex"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.15.4"},{"fixed":"0.16.10"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2024/03/GHSA-cvr6-37gx-v8wc/GHSA-cvr6-37gx-v8wc.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}