CVE-2024-1135

Description

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.

Overview

State: PUBLISHED
Assigner (CNA): @huntr_ai
CVSS severity: HIGH
CVSS score: 7.5 / 10
CVSS vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Effective score: 7.5 / 10 HIGH source: CNA overview
CWE(s): CWE-444
Reserved: 2024-01-31
Published: 2024-04-16 00:00 UTC
Last updated: 2025-02-13 17:27 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2024/1xxx/CVE-2024-1135.json
Linked Threat: CVE-2024-1135 — Impact of CVE-2024-1135

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2024-04-16 00:15:07 UTC
NVD last modified: 2026-04-15 00:35:42 UTC
EPSS score: 0.0005 (probability of exploitation in next 30 days)
EPSS percentile: 15.47% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2024-1316
Assigner: @huntr_ai
Published: Apr 16, 2024, 12:00:14 AM
Updated: Feb 13, 2025, 5:27:34 PM
EUVD base score (CVSS 3.0): 7.5 / 10
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EUVD-reported EPSS: 0.0500
Vendors: benoitc
Products: benoitc/gunicorn (unspecified ≤latest)

benoitc/gunicorn
Aliases: GHSA-w3h3-4rj7-4ph4

ENISA description: 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.

EUVD references (2)

Affected products (1)

Vendor	Product	Versions	Platforms
benoitc	benoitc/gunicorn	`unspecified` (affected)	—

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

MITRE references (2) cveawg.mitre.org

Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.

Web references (4)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

http://cwe.mitre.org/data/definitions/444.html rapid7:cwe.mitre.org
https://attackerkb.com/topics/CVE-2024-1135 rapid7:attackerkb.com
https://euvd.enisa.europa.eu/vulnerability/EUVD-2024-1316 rapid7:euvd.enisa.europa.eu
https://www.cve.org/CVERecord?id=CVE-2024-1135 rapid7:www.cve.org

NVD-tagged references (5)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1 security@huntr.dev
https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1 af854a3a-2127-422b-91ae-364da2661108
https://lists.debian.org/debian-lts-announce/2024/06/msg00027.html security@huntr.dev
https://lists.debian.org/debian-lts-announce/2024/06/msg00027.html af854a3a-2127-422b-91ae-364da2661108
https://lists.debian.org/debian-lts-announce/2024/12/msg00018.html af854a3a-2127-422b-91ae-364da2661108

Indicators (1)

IOCs linked to the auto-promoted Threat row.

Type	Value	VirusTotal	Attached
cve	`CVE-2024-1135`	no local data	2026-05-14 09:34 UTC

Remediations (8)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-05-17 09:25 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Access Microsoft Security Response Center's guide to address vulnerabilities, manage security risks, and keep your systems protected with the latest updates.

2026-05-17 09:25 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-05-17 09:25 UTC
Landing Page | ServiceNow Common Vulnerabilities & Exposures (CVE ...

web:support.servicenow.com

Overview The advisories below document publicly disclosed Common Vulnerabilities and Exposures ( CVEs ) in the Now Platform by ServiceNow. Because ServiceNow uses various methods to communicate vulnerability information, patches, and other fixes, customers should review family, security patch , and hotfix release notes, which are available at https://docs.servicenow.com, for a complete list of ...

2026-05-17 09:25 UTC
CISA Adds Five Known Exploited Vulnerabilities to Catalog

web:www.cisa.gov

CISA has added five new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation.

2026-05-17 09:25 UTC
November 2025 Patch Tuesday: Updates and Analysis | CrowdStrike

web:www.crowdstrike.com

Microsoft has released security updates for 63 vulnerabilities, including 1 zero-day and 4 critical vulnerabilities, in its November 2025 Patch Tuesday rollout.

2026-05-17 09:25 UTC
Microsoft Technical Security Notifications

web:www.microsoft.com

Security Update Guide Notifications Microsoft's free Security Update Guide Notifications provide links to security-related software updates and notification of re-released security updates. These notifications are sent via email throughout the month as needed.

2026-05-17 09:25 UTC
CVE-2024-1135 Common Vulnerabilities and Exposures | SUSE

web:www.suse.com

Secure your Linux systems from CVE-2024-1135 . Stay ahead of potential threats with the latest security updates from SUSE.

2026-05-17 09:25 UTC

AI Forensic Analysis

Only Available for Registered Users. Sign in to view.

Raw JSON

The full cvelistV5 record. Download as CVE-2024-1135.json.

{
  "containers": {
    "adp": [
      {
        "affected": [
          {
            "cpes": [
              "cpe:2.3:a:benoitc:gunicorn:*:*:*:*:*:*:*:*"
            ],
            "defaultStatus": "unknown",
            "product": "gunicorn",
            "vendor": "benoitc",
            "versions": [
              {
                "status": "affected",
                "version": "*"
              }
            ]
          }
        ],
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2024-1135",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-04-19T17:32:23.631972Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-06-04T17:59:56.871Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-12-20T07:02:46.961Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00027.html"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2024/12/msg00018.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "benoitc/gunicorn",
          "vendor": "benoitc",
          "versions": [
            {
              "lessThanOrEqual": "latest",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_0": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
            "version": "3.0"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-444",
              "description": "CWE-444 Inconsistent Interpretation of HTTP Requests",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2024-06-30T23:06:05.937Z",
        "orgId": "c09c270a-b464-47c1-9133-acb35b22c19a",
        "shortName": "@huntr_ai"
      },
      "references": [
        {
          "url": "https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1"
        },
        {
          "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00027.html"
        }
      ],
      "source": {
        "advisory": "22158e34-cfd5-41ad-97e0-a780773d96c1",
        "discovery": "EXTERNAL"
      },
      "title": "HTTP Request Smuggling in benoitc/gunicorn"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "c09c270a-b464-47c1-9133-acb35b22c19a",
    "assignerShortName": "@huntr_ai",
    "cveId": "CVE-2024-1135",
    "datePublished": "2024-04-16T00:00:14.938Z",
    "dateReserved": "2024-01-31T18:15:14.296Z",
    "dateUpdated": "2025-02-13T17:27:34.444Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}