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Medium, CVSS 6.5amended

KaTeX's maxExpand bypassed by Unicode sub/superscripts

CVE-2024-28244GHSA-cvr6-37gx-v8wc

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (katex 0.16.10), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • npm katex

    Affected
    >= 0.15.4, < 0.16.10
    Fixed in
    0.16.10

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2024-28244: 2.15% estimated exploitation activity in the next 30 days; percentile 82.19 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Impact KaTeX 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. Patches Upgrade to KaTeX v0.16.10 to remove this vulnerability. Workarounds Forbid inputs containing any of the characters ₊₋₌₍₎₀₁₂₃₄₅₆₇₈₉ₐₑₕᵢⱼₖₗₘₙₒₚᵣₛₜᵤᵥₓᵦᵧᵨᵩᵪ⁺⁻⁼⁽⁾⁰¹²³⁴⁵⁶⁷⁸⁹ᵃᵇᶜᵈᵉᵍʰⁱʲᵏˡᵐⁿᵒᵖʳˢᵗᵘʷˣʸᶻᵛᵝᵞᵟᵠᵡ before passing them to KaTeX. (There is no easy workaround for the auto-render extension.) Details KaTeX 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" allows an attacker to bypass this limit. Each…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-cvr6-37gx-v8wc

  2. Revision 1 · created ·

    Published from osv record GHSA-cvr6-37gx-v8wc

Agent brief

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# Patch Next advisory brief: CVE-2024-28244

Advisory: KaTeX's maxExpand bypassed by Unicode sub/superscripts
IDs: CVE-2024-28244, GHSA-cvr6-37gx-v8wc
Record: https://patchnext.com/advisories/cve-2024-28244 (revision 2, source checked 26 Oct 2026, 12:30 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: katex 0.16.10. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm katex: affected >= 0.15.4, < 0.16.10; fixed in 0.16.10

## Suggested inspection (read-only)
- `npm ls katex --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on katex.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-cvr6-37gx-v8wc (OSV record GHSA-cvr6-37gx-v8wc lists affected ranges: npm katex >=0.15.4 <0.16.10 (fixed))
- Verified: https://github.com/advisories/GHSA-cvr6-37gx-v8wc (GitHub-reviewed advisory GHSA-cvr6-37gx-v8wc lists affected ranges: npm katex >=0.15.4 <0.16.10)

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