FKIE_CVE-2026-68750

Vulnerability from fkie_nvd - Published: 2026-08-06 16:16 - Updated: 2026-08-07 13:48
Severity
8.2 (High) - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Summary
Inefficient Algorithmic Complexity vulnerability in the traversal engine in rrrene html_sanitize_ex allows an unauthenticated remote attacker to exhaust server CPU and memory via a flat run of sibling elements in sanitized HTML. The list clause of HtmlSanitizeEx.Traverser.traverse/2 recurses on the tail of a sibling list and then evaluates List.flatten([head] ++ tail) over the already flattened result, so every one of n siblings copies and re-walks the entire remaining tail. The flattening is only needed for the rare case where scrub returns several replacement nodes for one node, but the cost is paid across the whole tail at every step, making traversal quadratic in sibling count. The traverser sits on every public entry point, so no particular scrubber or configuration is required and the payload needs only allowed tags. A 160 KB body of 20,000 sibling elements occupies a scheduler for roughly 1.7 seconds, and the cost grows faster than the body does. This issue affects html_sanitize_ex: from 0.3.1 before 1.5.3.
References
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://cna.erlef.org/cves/CVE-2026-68750.html
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/rrrene/html_sanitize_ex/commit/9f5ccedbed230930813f992a1e6906fcf485981e
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-463q-p2fr-mh9p
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://osv.dev/vulnerability/EEF-CVE-2026-68750
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.HtmlSanitizeEx.Traverser\u0027",
            "\u0027Elixir.HtmlSanitizeEx\u0027"
          ],
          "packageName": "html_sanitize_ex",
          "packageURL": "pkg:hex/html_sanitize_ex",
          "product": "html_sanitize_ex",
          "programFiles": [
            "lib/html_sanitize_ex/traverser.ex",
            "lib/html_sanitize_ex.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.HtmlSanitizeEx.Traverser\u0027:traverse/2"
            },
            {
              "name": "\u0027Elixir.HtmlSanitizeEx\u0027:basic_html/1"
            },
            {
              "name": "\u0027Elixir.HtmlSanitizeEx\u0027:html5/1"
            },
            {
              "name": "\u0027Elixir.HtmlSanitizeEx\u0027:markdown_html/1"
            },
            {
              "name": "\u0027Elixir.HtmlSanitizeEx\u0027:strip_tags/1"
            }
          ],
          "repo": "https://github.com/rrrene/html_sanitize_ex",
          "vendor": "rrrene",
          "versions": [
            {
              "lessThan": "1.5.3",
              "status": "affected",
              "version": "0.3.1",
              "versionType": "semver"
            }
          ]
        },
        {
          "collectionURL": "https://github.com",
          "cpes": [
            "cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.HtmlSanitizeEx.Traverser\u0027",
            "\u0027Elixir.HtmlSanitizeEx\u0027"
          ],
          "packageName": "rrrene/html_sanitize_ex",
          "packageURL": "pkg:github/rrrene/html_sanitize_ex",
          "product": "html_sanitize_ex",
          "programFiles": [
            "lib/html_sanitize_ex/traverser.ex",
            "lib/html_sanitize_ex.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.HtmlSanitizeEx.Traverser\u0027:traverse/2"
            },
            {
              "name": "\u0027Elixir.HtmlSanitizeEx\u0027:basic_html/1"
            },
            {
              "name": "\u0027Elixir.HtmlSanitizeEx\u0027:html5/1"
            },
            {
              "name": "\u0027Elixir.HtmlSanitizeEx\u0027:markdown_html/1"
            },
            {
              "name": "\u0027Elixir.HtmlSanitizeEx\u0027:strip_tags/1"
            }
          ],
          "repo": "https://github.com/rrrene/html_sanitize_ex",
          "vendor": "rrrene",
          "versions": [
            {
              "lessThan": "9f5ccedbed230930813f992a1e6906fcf485981e",
              "status": "affected",
              "version": "69ea11d61525c470b39b6860d024770d5573ff1f",
              "versionType": "git"
            }
          ]
        }
      ],
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Inefficient Algorithmic Complexity vulnerability in the traversal engine in rrrene html_sanitize_ex allows an unauthenticated remote attacker to exhaust server CPU and memory via a flat run of sibling elements in sanitized HTML. The list clause of HtmlSanitizeEx.Traverser.traverse/2 recurses on the tail of a sibling list and then evaluates List.flatten([head] ++ tail) over the already flattened result, so every one of n siblings copies and re-walks the entire remaining tail. The flattening is only needed for the rare case where scrub returns several replacement nodes for one node, but the cost is paid across the whole tail at every step, making traversal quadratic in sibling count.\n\nThe traverser sits on every public entry point, so no particular scrubber or configuration is required and the payload needs only allowed tags. A 160 KB body of 20,000 sibling elements occupies a scheduler for roughly 1.7 seconds, and the cost grows faster than the body does.\n\nThis issue affects html_sanitize_ex: from 0.3.1 before 1.5.3."
    }
  ],
  "id": "CVE-2026-68750",
  "lastModified": "2026-08-07T13:48:52.300",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.2,
          "baseSeverity": "HIGH",
          "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": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "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-2026-68750",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-06T15:41:21.489983Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-06T16:16:51.907",
  "references": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://cna.erlef.org/cves/CVE-2026-68750.html"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://github.com/rrrene/html_sanitize_ex/commit/9f5ccedbed230930813f992a1e6906fcf485981e"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-463q-p2fr-mh9p"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-68750"
    }
  ],
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-407"
        }
      ],
      "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.

Sightings

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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.
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Detection rules are retrieved from Rulezet.