{"cve":"CVE-2026-54888","nvd":{"published":"2026-06-29T20:17:39.230","modified":"2026-06-30T14:14:35.520","status":"Deferred","description":"Uncontrolled Recursion vulnerability in leandrocp mdex allows denial of service via deeply nested Markdown input.\n\nmdex converts between an Elixir %MDEx.Document{} struct and Comrak's internal AST using two mutually recursive Rust functions, ex_document_to_comrak_ast and comrak_ast_to_ex_document, in the NIF source file document.rs. Neither function enforces a maximum nesting depth, so the recursion depth is bounded only by the structure of the input. An attacker who can get a Markdown document rendered (for example through MDEx.parse_document!/1 or MDEx.to_html/1) can supply a document with thousands of nested block quotes, which drives unbounded recursion across the NIF boundary and exhausts the native C stack.\n\nBecause the resulting stack overflow is an uncatchable SIGSEGV raised inside a NIF, it cannot be contained by the Erlang runtime. It terminates the operating system process running the BEAM, killing every Elixir and Erlang process on the node, not just the caller that triggered the render. No authentication or special privileges are required.\n\nThe vulnerable conversion code was extracted from mdex into the separate mdex_native package starting in mdex 0.12.3. This issue affects mdex from 0.3.0 before 0.12.3 and mdex_native from 0.1.0 before 0.2.3.","cvss_v4":{"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","score":6.9},"cvss_v3":null,"cwes":["CWE-674"],"references":["https://cna.erlef.org/cves/CVE-2026-54888.html","https://github.com/leandrocp/mdex_native/commit/947696c47bc22bea5dffc0f78c946fa6b70ce183","https://github.com/leandrocp/mdex_native/security/advisories/GHSA-3w4f-53g2-f66p","https://osv.dev/vulnerability/EEF-CVE-2026-54888","https://github.com/leandrocp/mdex_native/security/advisories/GHSA-3w4f-53g2-f66p"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:41:17.107060303+00:00"},"epss":{"cve":"CVE-2026-54888","score":0.00237,"percentile":0.148,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}