ratex-parser has unbounded parser recursion that leads to stack overflow (process abort)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-53531: 0.43% estimated exploitation activity in the next 30 days; percentile 36.89 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary RaTeX’s recursive-descent parser recurses one (or more) native stack frame per nesting level at {, \left, \sqrt{, ^{, etc, with no maximum depth limit. A short, ~10 KB input of nested groups overflows the 8 MB main-thread stack and aborts the process. With panic = "abort" (Cargo.toml:48), and because a Rust stack overflow is always a fatal SIGABRT regardless of panic strategy this is an unrecoverable, whole-process denial of service reachable from a single untrusted LaTeX string. Details The mutual recursion has no depth guard (crates/ratex-parser/src/parser.rs): \left adds another recursive edge: handleleft → parseexpression (crates/ratex-parser/src/functions/leftright.rs:47). The only counters present are unrelated to depth: leftrightdepth (a \right-matching counter, parser.rs:24) and the macro expander’s maxexpand = 1000 (macroexpander.rs:64), which does not gate brace / \left recursion (those tokens never pass through expandonce). There is no recursionlimit/depth…

Published by the source

7 Jul 2026, 23:39 UTC

Last modified by the source

7 Jul 2026, 23:39 UTC

Source last checked

26 Oct 2026, 15:43 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4w5h-hx6r-28q7

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# Patch Next advisory brief: CVE-2026-53531

Advisory: ratex-parser has unbounded parser recursion that leads to stack overflow (process abort)
IDs: CVE-2026-53531, GHSA-4w5h-hx6r-28q7
Record: https://patchnext.com/advisories/cve-2026-53531 (revision 1, source checked 26 Oct 2026, 15:43 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: ratex-parser 0.1.11. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io ratex-parser: affected < 0.1.11; fixed in 0.1.11

## Suggested inspection (read-only)
- crates.io ratex-parser: check the installed version with your package manager.

## 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 ratex-parser.
- 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://github.com/advisories/GHSA-4w5h-hx6r-28q7 (GitHub-reviewed advisory GHSA-4w5h-hx6r-28q7 lists affected ranges: crates.io ratex-parser >=0 <0.1.11)

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