FKIE_CVE-2026-53427

Vulnerability from fkie_nvd - Published: 2026-06-29 19:16 - Updated: 2026-06-29 20:17
Severity
2.3 (Low) - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Summary
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in leandrocp MDEx allows stored or reflected cross-site scripting via attacker-controlled Markdown. When syntax highlighting and full info-string forwarding (render: [full_info_string: true]) are enabled, the Lumis adapter copies the value of a code fence's highlight_lines_class info-string attribute, unescaped, into the class attribute of every rendered line. comrak_nif::lumis_adapter::LumisAdapter::parse_custom_attributes in native/comrak_nif/src/lumis_adapter.rs shlex-parses the info string and stores each key=value pair verbatim, highlight_lines_config pulls highlight_lines_class into the per-line class value, and write_highlighted interpolates that value directly into the class attribute of the per-line <div>. A single-quoted shell token preserves an inner double quote through shlex parsing, so a value such as '"><script>alert(1)</script>' terminates the class attribute early and the markup that follows is emitted as live HTML. An attacker who can submit Markdown (through comments, posts, wiki pages, documentation, or any user-generated content) can inject arbitrary HTML and JavaScript that runs in the browser of every user who views the rendered output, enabling session theft, account takeover, and other client-side attacks. No authentication or special privileges are required. The vulnerable native code originally shipped inside mdex (in native/comrak_nif/src/lumis_adapter.rs) and was later extracted into the separate mdex_native package (native/mdex_native_nif/src/lumis_adapter.rs), where it remains unpatched. This issue affects mdex from 0.11.3 before 0.12.3, and mdex_native from 0.1.0 before 0.2.3.
References
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://cna.erlef.org/cves/CVE-2026-53427.html
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/leandrocp/mdex_native/commit/798a363b4339f6f7162ec8437c4c9f9b5ae6fbf3
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/leandrocp/mdex_native/security/advisories/GHSA-v664-pmxr-mxxx
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://osv.dev/vulnerability/EEF-CVE-2026-53427
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:leandrocp:mdex:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.MDEx\u0027",
            "comrak_nif"
          ],
          "packageName": "mdex",
          "packageURL": "pkg:hex/mdex",
          "product": "mdex",
          "programFiles": [
            "native/comrak_nif/src/lumis_adapter.rs"
          ],
          "programRoutines": [
            {
              "name": "comrak_nif::lumis_adapter::LumisAdapter::parse_custom_attributes"
            },
            {
              "name": "comrak_nif::lumis_adapter::LumisAdapter::highlight_lines_config"
            },
            {
              "name": "comrak_nif::lumis_adapter::LumisAdapter::write_highlighted"
            },
            {
              "name": "\u0027Elixir.MDEx\u0027:to_html/2"
            }
          ],
          "repo": "https://github.com/leandrocp/mdex",
          "vendor": "leandrocp",
          "versions": [
            {
              "lessThan": "0.12.3",
              "status": "affected",
              "version": "0.11.3",
              "versionType": "semver"
            }
          ]
        },
        {
          "collectionURL": "https://github.com",
          "cpes": [
            "cpe:2.3:a:leandrocp:mdex:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.MDEx\u0027",
            "comrak_nif"
          ],
          "packageName": "leandrocp/mdex",
          "packageURL": "pkg:github/leandrocp/mdex",
          "product": "mdex",
          "programFiles": [
            "native/comrak_nif/src/lumis_adapter.rs"
          ],
          "programRoutines": [
            {
              "name": "comrak_nif::lumis_adapter::LumisAdapter::parse_custom_attributes"
            },
            {
              "name": "comrak_nif::lumis_adapter::LumisAdapter::highlight_lines_config"
            },
            {
              "name": "comrak_nif::lumis_adapter::LumisAdapter::write_highlighted"
            },
            {
              "name": "\u0027Elixir.MDEx\u0027:to_html/2"
            }
          ],
          "repo": "https://github.com/leandrocp/mdex",
          "vendor": "leandrocp",
          "versions": [
            {
              "lessThan": "6ed94d905f97af188323f042698ae841c02293b4",
              "status": "affected",
              "version": "0d7ffc84ea742e1daf666426814e5bb6d0499433",
              "versionType": "git"
            }
          ]
        },
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:leandrocp:mdex_native:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.MDExNative.Comrak\u0027",
            "mdex_native_nif"
          ],
          "packageName": "mdex_native",
          "packageURL": "pkg:hex/mdex_native",
          "product": "mdex_native",
          "programFiles": [
            "native/mdex_native_nif/src/lumis_adapter.rs"
          ],
          "programRoutines": [
            {
              "name": "mdex_native_nif::lumis_adapter::LumisAdapter::parse_custom_attributes"
            },
            {
              "name": "mdex_native_nif::lumis_adapter::LumisAdapter::highlight_lines_config"
            },
            {
              "name": "mdex_native_nif::lumis_adapter::LumisAdapter::write_highlighted"
            },
            {
              "name": "\u0027Elixir.MDExNative.Native\u0027:document_to_html_with_options/2"
            },
            {
              "name": "\u0027Elixir.MDExNative.Comrak\u0027:document_to_html/2"
            }
          ],
          "repo": "https://github.com/leandrocp/mdex_native",
          "vendor": "leandrocp",
          "versions": [
            {
              "lessThan": "0.2.3",
              "status": "affected",
              "version": "0.1.0",
              "versionType": "semver"
            }
          ]
        },
        {
          "collectionURL": "https://github.com",
          "cpes": [
            "cpe:2.3:a:leandrocp:mdex_native:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.MDExNative.Comrak\u0027",
            "mdex_native_nif"
          ],
          "packageName": "leandrocp/mdex_native",
          "packageURL": "pkg:github/leandrocp/mdex_native",
          "product": "mdex_native",
          "programFiles": [
            "native/mdex_native_nif/src/lumis_adapter.rs"
          ],
          "programRoutines": [
            {
              "name": "mdex_native_nif::lumis_adapter::LumisAdapter::parse_custom_attributes"
            },
            {
              "name": "mdex_native_nif::lumis_adapter::LumisAdapter::highlight_lines_config"
            },
            {
              "name": "mdex_native_nif::lumis_adapter::LumisAdapter::write_highlighted"
            },
            {
              "name": "\u0027Elixir.MDExNative.Native\u0027:document_to_html_with_options/2"
            },
            {
              "name": "\u0027Elixir.MDExNative.Comrak\u0027:document_to_html/2"
            }
          ],
          "repo": "https://github.com/leandrocp/mdex_native",
          "vendor": "leandrocp",
          "versions": [
            {
              "lessThan": "798a363b4339f6f7162ec8437c4c9f9b5ae6fbf3",
              "status": "affected",
              "version": "956528c5e31746253347029e810a969ab916fd27",
              "versionType": "git"
            }
          ]
        }
      ],
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027) vulnerability in leandrocp MDEx allows stored or reflected cross-site scripting via attacker-controlled Markdown.\n\nWhen syntax highlighting and full info-string forwarding (render: [full_info_string: true]) are enabled, the Lumis adapter copies the value of a code fence\u0027s highlight_lines_class info-string attribute, unescaped, into the class attribute of every rendered line. comrak_nif::lumis_adapter::LumisAdapter::parse_custom_attributes in native/comrak_nif/src/lumis_adapter.rs shlex-parses the info string and stores each key=value pair verbatim, highlight_lines_config pulls highlight_lines_class into the per-line class value, and write_highlighted interpolates that value directly into the class attribute of the per-line \u003cdiv\u003e. A single-quoted shell token preserves an inner double quote through shlex parsing, so a value such as \u0027\"\u003e\u003cscript\u003ealert(1)\u003c/script\u003e\u0027 terminates the class attribute early and the markup that follows is emitted as live HTML.\n\nAn attacker who can submit Markdown (through comments, posts, wiki pages, documentation, or any user-generated content) can inject arbitrary HTML and JavaScript that runs in the browser of every user who views the rendered output, enabling session theft, account takeover, and other client-side attacks. No authentication or special privileges are required.\n\nThe vulnerable native code originally shipped inside mdex (in native/comrak_nif/src/lumis_adapter.rs) and was later extracted into the separate mdex_native package (native/mdex_native_nif/src/lumis_adapter.rs), where it remains unpatched.\n\nThis issue affects mdex from 0.11.3 before 0.12.3, and mdex_native from 0.1.0 before 0.2.3."
    }
  ],
  "id": "CVE-2026-53427",
  "lastModified": "2026-06-29T20:17:38.650",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 2.3,
          "baseSeverity": "LOW",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "LOW",
          "subIntegrityImpact": "LOW",
          "userInteraction": "PASSIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-53427",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-29T19:18:13.166991Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-06-29T19:16:41.597",
  "references": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://cna.erlef.org/cves/CVE-2026-53427.html"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://github.com/leandrocp/mdex_native/commit/798a363b4339f6f7162ec8437c4c9f9b5ae6fbf3"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://github.com/leandrocp/mdex_native/security/advisories/GHSA-v664-pmxr-mxxx"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-53427"
    }
  ],
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "type": "Secondary"
    }
  ]
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.