{"cve":"CVE-2026-53426","nvd":{"published":"2026-06-29T20:17:38.473","modified":"2026-10-25T21:10:00.770","status":"Deferred","description":"Allocation of Resources Without Limits or Throttling vulnerability in leandrocp MDEx allows Excessive Allocation.\n\nMDEx.parse_document/2 accepts a {:json, json} source. In lib/mdex.ex, the private json_to_node/1 function passes the attacker-controlled node_type value to Module.concat/1, which calls String.to_atom/1 and interns a brand-new atom for every distinct value. Atoms are never garbage collected on the BEAM, so a crafted JSON document carrying a unique node_type at each (deeply nested) node mints one permanent atom per node.\n\nA single document can intern hundreds of thousands of atoms, and a large enough document exhausts the default atom table (around 1,048,576 atoms) and aborts the entire Erlang VM, taking down every process on the node. Any application that passes untrusted input to the {:json, ...} source of MDEx.parse_document is exposed to an unauthenticated denial-of-service.\n\nThis issue affects mdex from 0.4.3 before 0.13.2.","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:H","score":8.2},"cvss_v3":null,"cwes":["CWE-770"],"references":["https://cna.erlef.org/cves/CVE-2026-53426.html","https://github.com/leandrocp/mdex/commit/00fddf444220a1f1cc0af0a1cab6738804878387","https://github.com/leandrocp/mdex/security/advisories/GHSA-923r-7vf4-5vw8","https://osv.dev/vulnerability/EEF-CVE-2026-53426"],"products":[],"source":"nvd","synced_at":"2026-10-25T23:44:33.281319194+00:00"},"epss":{"cve":"CVE-2026-53426","score":0.0018,"percentile":0.07497,"date":"2026-10-25"},"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."]}