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CVE-2024-1135

Status: DeferredHigh (7.5)—

Gunicorn fails to properly validate Transfer-Encoding headers, leading to HTTP Request Smuggling (HRS) vulnerabilities. By crafting requests with conflicting Transfer-Encoding headers, attackers can bypass security restrictions and access restricted endpoints. This issue is due to Gunicorn's handling of Transfer-Encoding headers, where it incorrectly processes requests with multiple, conflicting Transfer-Encoding headers, treating them as chunked regardless of the final encoding specified. This vulnerability allows for a range of attacks including cache poisoning, session manipulation, and data exposure.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Gunicorn — GunicornAI

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2024-1135",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2024-1135",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2024-04-19T17:32:23.631972Z"
        }
      }
    ],
    "cvssMetricV30": [
      {
        "type": "Secondary",
        "source": "security@huntr.dev",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security@huntr.dev",
      "affectedData": [
        {
          "vendor": "benoitc",
          "product": "benoitc/gunicorn",
          "versions": [
            {
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom",
              "lessThanOrEqual": "latest"
            }
          ]
        }
      ]
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "affectedData": [
        {
          "cpes": [
            "cpe:2.3:a:benoitc:gunicorn:*:*:*:*:*:*:*:*"
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          "product": "gunicorn",
          "versions": [
            {
              "status": "affected",
              "version": "*"
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          "defaultStatus": "unknown"
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  ],
  "published": "2024-04-16T00:15:07.797",
  "references": [
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      "url": "https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1",
      "source": "security@huntr.dev"
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    {
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00027.html",
      "source": "security@huntr.dev"
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    {
      "url": "https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
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    {
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00027.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
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    {
      "url": "https://lists.debian.org/debian-lts-announce/2024/12/msg00018.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security@huntr.dev",
      "description": [
        {
          "lang": "en",
          "value": "CWE-444"
        }
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  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Gunicorn fails to properly validate Transfer-Encoding headers, leading to HTTP Request Smuggling (HRS) vulnerabilities. By crafting requests with conflicting Transfer-Encoding headers, attackers can bypass security restrictions and access restricted endpoints. This issue is due to Gunicorn's handling of Transfer-Encoding headers, where it incorrectly processes requests with multiple, conflicting Transfer-Encoding headers, treating them as chunked regardless of the final encoding specified. This vulnerability allows for a range of attacks including cache poisoning, session manipulation, and data exposure."
    },
    {
      "lang": "es",
      "value": "Gunicorn no puede validar correctamente los encabezados Transfer-Encoding, lo que genera vulnerabilidades de contrabando de solicitudes HTTP (HRS). Al manipular solicitudes con encabezados Transfer-Encoding conflictivos, los atacantes pueden eludir las restricciones de seguridad y acceder a endpoints restringidos. Este problema se debe al manejo que hace Gunicorn de los encabezados Transfer-Encoding, donde procesa incorrectamente solicitudes con múltiples encabezados Transfer-Encoding conflictivos, tratándolos como fragmentados independientemente de la codificación final especificada. Esta vulnerabilidad permite una variedad de ataques que incluyen envenenamiento de caché, manipulación de sesiones y exposición de datos."
    }
  ],
  "lastModified": "2026-06-17T07:03:32.610",
  "sourceIdentifier": "security@huntr.dev"
}