---
id: RUSTSEC-2026-0311
title: Stack overflow on deeply nested LaTeX input
summary: Stack overflow on deeply nested LaTeX input
severity: none
vendor: latex-rust
product: latex-rust
ecosystem: rust
affected:
  - 'latex-rust >= 0.0.0-0, < 1.0.5'
patched:
  - latex-rust 1.0.5
published: '2026-09-27'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T08:45:03.080376729Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/RUSTSEC-2026-0311'
references:
  - url: 'https://crates.io/crates/latex-rust'
  - url: 'https://rustsec.org/advisories/RUSTSEC-2026-0311.html'
  - url: 'https://github.com/jscarr64/LaTeX-Rust/issues/6'
  - url: 'https://github.com/jscarr64/LaTeX-Rust/pull/10'
  - url: 'https://github.com/jscarr64/LaTeX-Rust/releases/tag/v1.0.5'
tags:
  - osv
  - rust
ingestedAt: '2026-09-29T07:20:57.380Z'
---

## Overview

The parser and layout engine in affected versions of `latex-rust` recurse once
per level of nesting with no limit. Deeply nested input, such as `\frac{1}{…}`,
braces, `\sqrt{…}`, `\left(`, or superscripts nested hundreds or thousands of
levels deep, exhausts the call stack.

A stack overflow in Rust aborts the process. It is not a panic, so it cannot be
caught with `catch_unwind`. A program that renders LaTeX from untrusted input
can therefore be terminated by a short string. With a release build on an 8 MiB
stack, 700 nested `\frac{1}{…}` (about 7 KB of input) abort version 1.0.4, and
10,000 nested braces (about 20 KB) abort it as well. The threshold is lower on
smaller stacks and in debug builds; on a 2 MiB thread in a debug build, about
35 nested fractions are enough.

```rust
let mut src = String::from("1");
for _ in 0..700 {
    src = format!("\\frac{{1}}{{{src}}}");
}
let _ = latex_rust::parse(&src); // stack overflow, process aborts
```

The fixed versions count nesting depth in the parser and in `layout` and
refuse input that nests more than 32 levels. `parse`, `parse_with_colors`, and
the `latex_to_*` functions return
`ParseError::Malformed("input nests deeper than 32 levels")`, and `layout`
returns `Error::Unsupported { what: "tree nests deeper than 32 levels" }` for a
tree built by hand. The count is of parser recursion levels, and a braced
argument costs two, so the limit admits 15 nested `\frac`, `\sqrt`, or
`x^{…}`, and 31 nested groups, `\left…\right` pairs, or environments. Input
past the limit is refused within about 100 KiB of stack in an optimised build.

Version 1.0.5 fixes this with no API changes and is a drop-in replacement for
1.0.4; upgrade with `cargo update -p latex-rust`. It also includes the 2.0.0
rendering fixes, so rendered output differs from 1.0.4. Versions 2.0.0 and
2.0.1 contain the same fix, with the same limit and messages, together with
breaking API changes relative to 1.x, and also let callers change the limit
with `ParseOptions` and `layout_with_max_depth`.

## Affected packages

- `latex-rust >= 0.0.0-0, < 1.0.5`

## Remediation

Upgrade to a patched release:

- `latex-rust 1.0.5`