ratex-parser panics on \verb with a multibyte delimiter (UTF-8 byte-boundary slice)

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-53530: 0.43% estimated exploitation activity in the next 30 days; percentile 37.09 (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 The public parser entrypoint ratexparser::parse(&str) panics on the 9-byte input \verbéxé (i.e. \verb followed by the non-ASCII delimiter é). When handling a \verb command, the parser slices the verbatim argument with byte indices (arg[1..arg.len() - 1]); if the delimiter character is multibyte UTF-8, index 1 lands inside that character and Rust panics with “byte index 1 is not a char boundary”. Because RaTeX’s release profile sets panic = "abort" (Cargo.toml:48), the panic aborts the entire process — not just the current request/thread — making this a hard denial of service for any service that renders untrusted LaTeX. Details Affected code crates/ratex-parser/src/parser.rs, parsesymbolinner: For input \verbéxé: arg = "éxé", where é = U+00E9 (bytes C3 A9). arg.len() is the byte length (5), the < 2 guard passes, and arg[1..4] starts at byte index 1 — inside the first é (bytes 0..2) — so the slice panics. The lexer groups \verb<delim…<delim correctly with char semantics…

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-4hgp-59h5-gvrj

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# Patch Next advisory brief: CVE-2026-53530

Advisory: ratex-parser panics on `\verb` with a multibyte delimiter (UTF-8 byte-boundary slice)
IDs: CVE-2026-53530, GHSA-4hgp-59h5-gvrj
Record: https://patchnext.com/advisories/cve-2026-53530 (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: High (CVSS 8.7)
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-4hgp-59h5-gvrj (GitHub-reviewed advisory GHSA-4hgp-59h5-gvrj lists affected ranges: crates.io ratex-parser >=0 <0.1.11)

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