The ratex-parser crate's parse function panics on input such as `\verbéxé` where the delimiter `é` is a multibyte UTF-8 character. The parser incorrectly slices the argument string by byte indices (e.g., `arg[1..arg.len()-1]`), which can start slicing inside a multibyte character, causing a Rust panic with "byte index 1 is not a char boundary." Because the crate is built with `panic = "abort"`, this panic terminates the entire process, causing a hard denial of service. The lexer correctly handles multibyte delimiters, but the parser does not. The vulnerability affects versions of ratex-parser prior to 0.1.11. The recommended fix is to slice by character boundaries instead of byte indices and reconsider the use of `panic = "abort"` in long-running services.

Any application using ratex-parser to render untrusted LaTeX input can be crashed by a specially crafted string containing a \verb command with a multibyte UTF-8 delimiter. The panic aborts the entire process, causing a denial of service that can take down servers or batch pipelines processing LaTeX. This vulnerability does not require privileges or user interaction beyond supplying the crafted input and can disrupt availability of services relying on this parser.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The direct remediation is to fix the parser to slice strings by character boundaries rather than byte indices when handling \verb commands with multibyte delimiters. Additionally, consider avoiding `panic = "abort"` in release builds for long-running services and use `catch_unwind` to isolate panics. Until a patch is available, avoid processing untrusted LaTeX input with vulnerable versions of ratex-parser.