{"id":"CVE-2026-53531","aliases":["EUVD-2026-64180","GHSA-4w5h-hx6r-28q7"],"status":"published","title":"ratex-parser has unbounded parser recursion that leads to stack overflow (process abort)","description":"RaTeX is a KaTeX-compatible math rendering engine written in Rust. Prior to version 0.1.11, 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. Version 0.1.11 fixes the issue.","severity":{"version":"4.0","score":6.9,"vector":"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00426,"percentile":0.37157,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-400","CWE-674"],"published":"2026-07-07T23:39:30Z","modified":"2026-10-28T02:30:59Z","fixes":[{"ecosystem":"crates.io","package":"ratex-parser","fixed_in":["0.1.11"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"ratex-parser","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.1.11"}]}]},{"source":"osv","ecosystem":"crates.io","package":"ratex-parser","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.1.11"}]}]}],"products":[{"vendor":"erweixin","product":"ratex"}],"references":[{"url":"https://github.com/erweixin/RaTeX/security/advisories/GHSA-4w5h-hx6r-28q7","tags":["x_refsource_CONFIRM","exploit","advisory","web"]},{"url":"https://github.com/advisories/GHSA-4w5h-hx6r-28q7"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53531.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53531","tags":["advisory"]},{"url":"https://github.com/erweixin/RaTeX","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-53531","title":"ratex-parser has unbounded parser recursion that leads to stack overflow (process abort)","description":"RaTeX is a KaTeX-compatible math rendering engine written in Rust. Prior to version 0.1.11, 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. Version 0.1.11 fixes the issue.","status":"published","published":"2026-08-21T21:34:16.017Z","modified":"2026-08-25T16:51:41.853Z","cvss":[{"version":"4.0","score":6.9,"vector":"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","level":"medium","assessor":"cna"}],"cwes":["CWE-400","CWE-674"],"updated_at":"2026-11-02T14:20:00.11477Z"}],"euvd":[{"id":"EUVD-2026-64180","description":"RaTeX is a KaTeX-compatible math rendering engine written in Rust. Prior to version 0.1.11, 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. Version 0.1.11 fixes the issue.","status":"published","published":"2026-08-21T21:34:16Z","modified":"2026-08-25T16:51:41Z","cvss":[{"version":"4.0","score":6.9,"vector":"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","level":"medium"}],"updated_at":"2026-11-02T18:01:32.513581Z"}],"ghsa":[{"id":"GHSA-4w5h-hx6r-28q7","title":"ratex-parser has unbounded parser recursion that leads to stack overflow (process abort)","description":"### Summary\n\n\nRaTeX’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.\n\n### Details\n\nThe mutual recursion has no depth guard (`crates/ratex-parser/src/parser.rs`):\n\n```\nparse_expression (:113)  -\u003e  parse_atom (:281/285)  -\u003e  parse_group (:451)\n                                  ^                          |\n                                  |   on '{' (:459) recurse  |\n                                  +--------------------------+\n```\n\n`\\left` adds another recursive edge: `handle_left` → `parse_expression` (`crates/ratex-parser/src/functions/left_right.rs:47`). The only counters present are unrelated to depth: `leftright_depth` (a `\\right`-matching counter, `parser.rs:24`) and the macro expander’s `max_expand = 1000` (`macro_expander.rs:64`), which does **not** gate brace / `\\left` recursion (those tokens never pass through `expand_once`). There is no `recursion_limit`/depth parameter on `parse_group`, `parse_expression`, or `parse_atom`.\n\n### PoC\n\n\u003cimg width=\"1097\" height=\"158\" alt=\"image\" src=\"https://github.com/user-attachments/assets/29b837a2-c455-4cb6-a055-514b31c999c6\" /\u003e\n\n\n```\n$ python3 -c 'import sys;sys.stdout.write(\"{\"*200000+\"x\"+\"}\"*200000)' | ./target/release/parse\nthread 'main' has overflowed its stack\nfatal runtime error: stack overflow, aborting\nAborted (core dumped)            # exit 134\n```\n\n(Other nesting forms work equally, e.g. `\\left(`×N, `\\sqrt{`×N, `^{`×N.)\n\n### Impact\n\nA single small request crashes the whole RaTeX process. In a typical server-side math-rendering service this is a reliable, unauthenticated DoS; on smaller worker-thread stacks (e.g. a 512 KB async runtime thread) only a few hundred bytes of nesting are required.","status":"published","published":"2026-07-07T23:39:30Z","modified":"2026-07-07T23:39:31Z","cvss":[{"version":"4.0","score":6.9,"vector":"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","level":"medium"}],"cwes":["CWE-400","CWE-674"],"updated_at":"2026-11-02T14:40:40.389795Z"}],"nvd":[{"id":"CVE-2026-53531","description":"RaTeX is a KaTeX-compatible math rendering engine written in Rust. Prior to version 0.1.11, 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. Version 0.1.11 fixes the issue.","status":"published","published":"2026-08-21T22:16:39.737Z","modified":"2026-10-12T16:10:00.22Z","cvss":[{"version":"4.0","score":6.9,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"}],"cwes":["CWE-400","CWE-674"],"updated_at":"2026-11-02T14:12:40.665005Z"}],"osv":[{"id":"CVE-2026-53531","title":"ratex-parser has unbounded parser recursion that leads to stack overflow (process abort)","description":"RaTeX is a KaTeX-compatible math rendering engine written in Rust. Prior to version 0.1.11, 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. Version 0.1.11 fixes the issue.","status":"published","published":"2026-08-21T21:34:16.017Z","modified":"2026-10-28T02:30:59.19972615Z","cvss":[{"version":"4.0","score":6.9,"vector":"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","level":"medium"}],"cwes":["CWE-400","CWE-674"],"updated_at":"2026-11-02T15:45:08.132336Z"},{"id":"GHSA-4w5h-hx6r-28q7","title":"ratex-parser has unbounded parser recursion that leads to stack overflow (process abort)","description":"### Summary\n\n\nRaTeX’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.\n\n### Details\n\nThe mutual recursion has no depth guard (`crates/ratex-parser/src/parser.rs`):\n\n```\nparse_expression (:113)  -\u003e  parse_atom (:281/285)  -\u003e  parse_group (:451)\n                                  ^                          |\n                                  |   on '{' (:459) recurse  |\n                                  +--------------------------+\n```\n\n`\\left` adds another recursive edge: `handle_left` → `parse_expression` (`crates/ratex-parser/src/functions/left_right.rs:47`). The only counters present are unrelated to depth: `leftright_depth` (a `\\right`-matching counter, `parser.rs:24`) and the macro expander’s `max_expand = 1000` (`macro_expander.rs:64`), which does **not** gate brace / `\\left` recursion (those tokens never pass through `expand_once`). There is no `recursion_limit`/depth parameter on `parse_group`, `parse_expression`, or `parse_atom`.\n\n### PoC\n\n\u003cimg width=\"1097\" height=\"158\" alt=\"image\" src=\"https://github.com/user-attachments/assets/29b837a2-c455-4cb6-a055-514b31c999c6\" /\u003e\n\n\n```\n$ python3 -c 'import sys;sys.stdout.write(\"{\"*200000+\"x\"+\"}\"*200000)' | ./target/release/parse\nthread 'main' has overflowed its stack\nfatal runtime error: stack overflow, aborting\nAborted (core dumped)            # exit 134\n```\n\n(Other nesting forms work equally, e.g. `\\left(`×N, `\\sqrt{`×N, `^{`×N.)\n\n### Impact\n\nA single small request crashes the whole RaTeX process. In a typical server-side math-rendering service this is a reliable, unauthenticated DoS; on smaller worker-thread stacks (e.g. a 512 KB async runtime thread) only a few hundred bytes of nesting are required.","status":"published","published":"2026-07-07T23:39:30Z","modified":"2026-07-07T23:56:32.234602Z","cvss":[{"version":"4.0","score":6.9,"vector":"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","level":"medium"}],"cwes":["CWE-400","CWE-674"],"updated_at":"2026-11-02T15:46:37.528068Z"}]}}