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CVE-2026-68749

Full vulnerability record from the local CVENow database.

Description

Inefficient Regular Expression Complexity vulnerability in the CSS scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to exhaust server CPU via a long CSS declaration in sanitized HTML. The declaration regex in HtmlSanitizeEx.Scrubber.CSS.scrub/1 matches the property name with an unbounded greedy [-\w]+ followed by a mandatory :, so a long run of word characters not followed by a colon makes the engine give back one character at a time and retry the colon at every start offset. The work is quadratic in the length of the run, and no length cap is applied to the CSS handed to the scrubber. An 80 KB <style> body costs roughly 2.4 seconds of scheduler time, so a few concurrent requests saturate the BEAM scheduler pool and make the application unresponsive. The impact is CPU exhaustion only. Nothing is read, modified or disclosed. This issue affects html_sanitize_ex: from 0.3.1 before 1.4.5 and from 1.5.0-rc.0 before 1.5.3.

Severity
HIGH
CVSS score
8.2 (v4.0)
Vulnerability status
Modified
Source identifier
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Published
2026-08-06 16:16:51.720000
Last modified
2026-10-24 16:10:00.153000
View original CVE JSON 
{
  "id": "CVE-2026-68749",
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "published": "2026-08-06T16:16:51.720",
  "lastModified": "2026-10-24T16:10:00.153",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Inefficient Regular Expression Complexity vulnerability in the CSS scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to exhaust server CPU via a long CSS declaration in sanitized HTML. The declaration regex in HtmlSanitizeEx.Scrubber.CSS.scrub/1 matches the property name with an unbounded greedy [-\\w]+ followed by a mandatory :, so a long run of word characters not followed by a colon makes the engine give back one character at a time and retry the colon at every start offset. The work is quadratic in the length of the run, and no length cap is applied to the CSS handed to the scrubber. An 80 KB <style> body costs roughly 2.4 seconds of scheduler time, so a few concurrent requests saturate the BEAM scheduler pool and make the application unresponsive.\n\nThe impact is CPU exhaustion only. Nothing is read, modified or disclosed.\n\nThis issue affects html_sanitize_ex: from 0.3.1 before 1.4.5 and from 1.5.0-rc.0 before 1.5.3."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de complejidad de expresión regular ineficiente en el depurador CSS en rrrene html_sanitize_ex permite a un atacante remoto no autenticado agotar la CPU del servidor a través de una declaración CSS larga en HTML saneado. La expresión regular de declaración en HtmlSanitizeEx.Scrubber.CSS.scrub/1 coincide con el nombre de la propiedad con un [-\\w]+ codicioso ilimitado seguido de un : obligatorio, por lo que una secuencia larga de caracteres de palabra no seguida por dos puntos hace que el motor retroceda un carácter a la vez y reintente los dos puntos en cada desplazamiento de inicio. El trabajo es cuadrático en la longitud de la secuencia, y no se aplica ningún límite de longitud al CSS entregado al depurador. Un cuerpo [style] de 80 KB cuesta aproximadamente 2.4 segundos de tiempo de planificador, por lo que unas pocas solicitudes concurrentes saturan el pool de planificadores BEAM y hacen que la aplicación no responda.\n\nEl impacto es solo agotamiento de CPU. Nada es leído, modificado o divulgado.\n\nEste problema afecta a html_sanitize_ex: desde 0.3.1 antes de 1.5.3."
    }
  ],
  "affected": [
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      "affectedData": [
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          "product": "html_sanitize_ex",
          "defaultStatus": "unaffected",
          "collectionURL": "https://repo.hex.pm",
          "packageName": "html_sanitize_ex",
          "cpes": [
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          "modules": [
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            "'Elixir.HtmlSanitizeEx'"
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          "programFiles": [
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            "lib/html_sanitize_ex.ex"
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          "programRoutines": [
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            },
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          "repo": "https://github.com/rrrene/html_sanitize_ex",
          "packageURL": "pkg:hex/html_sanitize_ex",
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              "versionType": "semver",
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          "programFiles": [
            "lib/html_sanitize_ex/scrubber/css.ex",
            "lib/html_sanitize_ex.ex"
          ],
          "programRoutines": [
            {
              "name": "'Elixir.HtmlSanitizeEx.Scrubber.CSS':scrub/1"
            },
            {
              "name": "'Elixir.HtmlSanitizeEx':html5/1"
            }
          ],
          "repo": "https://github.com/rrrene/html_sanitize_ex",
          "packageURL": "pkg:github/rrrene/html_sanitize_ex",
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              "versionType": "git",
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          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
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          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
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      "url": "https://cna.erlef.org/cves/CVE-2026-68749.html",
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}