CVE-2026-54888

Estado: AplazadaMedia (6.9)—

Uncontrolled Recursion vulnerability in leandrocp mdex allows denial of service via deeply nested Markdown input.

mdex 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.

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Because 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.

The 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

Versión: 4.0
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/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
Puntuación base: 6.9

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.24%
Percentil entre todas las CVEs puntuadas: 13
Fecha de la puntuación: 3/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (2)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Leandrocp — Mdex^AI Leandrocp — Mdex Native^AI

CWE

CWE-674

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-54888",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-54888",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-06-29T20:47:22.348133Z"
        }
      }
    ],
    "cvssMetricV40": [
      {
        "type": "Secondary",
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
          "baseScore": 6.9,
          "Automatable": "NOT_DEFINED",
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "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/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",
          "exploitMaturity": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "subIntegrityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "confidentialityRequirement": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
        }
      }
    ]
  },
  "affected": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "affectedData": [
        {
          "cpes": [
            "cpe:2.3:a:leandrocp:mdex:*:*:*:*:*:*:*:*"
          ],
          "repo": "https://github.com/leandrocp/mdex",
          "vendor": "leandrocp",
          "modules": [
            "comrak_nif",
            "'Elixir.MDEx'",
            "'Elixir.MDEx.Native'"
          ],
          "product": "mdex",
          "versions": [
            {
              "status": "affected",
              "version": "0.3.0",
              "lessThan": "0.12.3",
              "versionType": "semver"
            }
          ],
          "packageURL": "pkg:hex/mdex",
          "packageName": "mdex",
          "programFiles": [
            "native/comrak_nif/src/types/document.rs",
            "lib/mdex.ex",
            "lib/mdex/native.ex"
          ],
          "collectionURL": "https://repo.hex.pm",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "comrak_nif::types::document::ex_document_to_comrak_ast"
            },
            {
              "name": "comrak_nif::types::document::comrak_ast_to_ex_document"
            },
            {
              "name": "'Elixir.MDEx':parse_document!/1"
            },
            {
              "name": "'Elixir.MDEx':to_html/1"
            },
            {
              "name": "'Elixir.MDEx.Native':document_to_html_with_options/2"
            }
          ]
        },
        {
          "cpes": [
            "cpe:2.3:a:leandrocp:mdex:*:*:*:*:*:*:*:*"
          ],
          "repo": "https://github.com/leandrocp/mdex",
          "vendor": "leandrocp",
          "modules": [
            "comrak_nif",
            "'Elixir.MDEx'",
            "'Elixir.MDEx.Native'"
          ],
          "product": "mdex",
          "versions": [
            {
              "status": "affected",
              "version": "d0bc7d55177727c61d188ef465178ab3b81f4f2c",
              "lessThan": "6ed94d905f97af188323f042698ae841c02293b4",
              "versionType": "git"
            }
          ],
          "packageURL": "pkg:github/leandrocp/mdex",
          "packageName": "leandrocp/mdex",
          "programFiles": [
            "native/comrak_nif/src/types/document.rs",
            "lib/mdex.ex",
            "lib/mdex/native.ex"
          ],
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "comrak_nif::types::document::ex_document_to_comrak_ast"
            },
            {
              "name": "comrak_nif::types::document::comrak_ast_to_ex_document"
            },
            {
              "name": "'Elixir.MDEx':parse_document!/1"
            },
            {
              "name": "'Elixir.MDEx':to_html/1"
            },
            {
              "name": "'Elixir.MDEx.Native':document_to_html_with_options/2"
            }
          ]
        },
        {
          "cpes": [
            "cpe:2.3:a:leandrocp:mdex_native:*:*:*:*:*:*:*:*"
          ],
          "repo": "https://github.com/leandrocp/mdex_native",
          "vendor": "leandrocp",
          "modules": [
            "mdex_native_nif",
            "'Elixir.MDExNative.Native'"
          ],
          "product": "mdex_native",
          "versions": [
            {
              "status": "affected",
              "version": "0.1.0",
              "lessThan": "0.2.3",
              "versionType": "semver"
            }
          ],
          "packageURL": "pkg:hex/mdex_native",
          "packageName": "mdex_native",
          "programFiles": [
            "native/mdex_native_nif/src/types/document.rs",
            "lib/mdex_native/native.ex"
          ],
          "collectionURL": "https://repo.hex.pm",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "mdex_native_nif::types::document::ex_document_to_comrak_ast"
            },
            {
              "name": "mdex_native_nif::types::document::comrak_ast_to_ex_document"
            },
            {
              "name": "'Elixir.MDExNative.Native':parse_document/2"
            },
            {
              "name": "'Elixir.MDExNative.Native':document_to_html_with_options/2"
            }
          ]
        },
        {
          "cpes": [
            "cpe:2.3:a:leandrocp:mdex_native:*:*:*:*:*:*:*:*"
          ],
          "repo": "https://github.com/leandrocp/mdex_native",
          "vendor": "leandrocp",
          "modules": [
            "mdex_native_nif",
            "'Elixir.MDExNative.Native'"
          ],
          "product": "mdex_native",
          "versions": [
            {
              "status": "affected",
              "version": "956528c5e31746253347029e810a969ab916fd27",
              "lessThan": "947696c47bc22bea5dffc0f78c946fa6b70ce183",
              "versionType": "git"
            }
          ],
          "packageURL": "pkg:github/leandrocp/mdex_native",
          "packageName": "leandrocp/mdex_native",
          "programFiles": [
            "native/mdex_native_nif/src/types/document.rs",
            "lib/mdex_native/native.ex"
          ],
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "mdex_native_nif::types::document::ex_document_to_comrak_ast"
            },
            {
              "name": "mdex_native_nif::types::document::comrak_ast_to_ex_document"
            },
            {
              "name": "'Elixir.MDExNative.Native':parse_document/2"
            },
            {
              "name": "'Elixir.MDExNative.Native':document_to_html_with_options/2"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-06-29T20:17:39.230",
  "references": [
    {
      "url": "https://cna.erlef.org/cves/CVE-2026-54888.html",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/leandrocp/mdex_native/commit/947696c47bc22bea5dffc0f78c946fa6b70ce183",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/leandrocp/mdex_native/security/advisories/GHSA-3w4f-53g2-f66p",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-54888",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/leandrocp/mdex_native/security/advisories/GHSA-3w4f-53g2-f66p",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "description": [
        {
          "lang": "en",
          "value": "CWE-674"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "lastModified": "2026-06-30T14:14:35.520",
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
}