Vulnerability Description
Allocation of Resources Without Limits or Throttling vulnerability in leandrocp MDEx allows Excessive Allocation. MDEx.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. A 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. This issue affects mdex from 0.4.3 before 0.13.2.
Related Weaknesses (CWE)
References
- https://cna.erlef.org/cves/CVE-2026-53426.html
- https://github.com/leandrocp/mdex/commit/00fddf444220a1f1cc0af0a1cab673880487838
- https://github.com/leandrocp/mdex/security/advisories/GHSA-923r-7vf4-5vw8
- https://osv.dev/vulnerability/EEF-CVE-2026-53426
FAQ
What is CVE-2026-53426?
CVE-2026-53426 is a documented vulnerability. Allocation of Resources Without Limits or Throttling vulnerability in leandrocp MDEx allows Excessive Allocation. MDEx.parse_document/2 accepts a {:json, json} source. In lib/mdex.ex, the private jso...
How severe is CVE-2026-53426?
CVSS scoring is not yet available for CVE-2026-53426. Check NVD for updates.
Is there a patch for CVE-2026-53426?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.