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VulnerabilityPublished

CVE-2026-53426: leandrocp mdex · Unthrottled Resource Allocation

Affects leandrocp mdexSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High : upgrade to 0.13.2 soon.

Data as of 10 Nov 2026, 23:24 UTC

CVSS 4.0 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.13.2, 00fddf444220a1f1cc0af0a1cab6738804878387
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.

What to do

Upgrade mdex to 0.13.2; mdex to 00fddf444220a1f1cc0af0a1cab6738804878387.

Affected software

ProductAffectedFixed in
leandrocpmdexAffected
  • >=0.4.3 <0.13.2
Fixed in
  • 0.13.2
leandrocpmdexAffected
  • ≥ cbb59a3f792dbc343873adec3466f49c853dc309, < 00fddf444220a1f1cc0af0a1cab6738804878387
Fixed in
  • 00fddf444220a1f1cc0af0a1cab6738804878387
Hexmdexpkg:hex/mdexOther threatsAffected
  • >=0.4.3 <0.13.2
Fixed in
  • 0.13.2

CPE configurations (1)

  • cpe:2.3:a:leandrocp:mdex:*:*:*:*:*:*:*:*

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, avoid passing untrusted JSON input to mdex.parse_document/2 with the {:json, ...} source. Consider implementing input validation or limiting JSON complexity to prevent excessive atom creation.

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.

References

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