{
  "schema_version": "1.5.0",
  "id": "CURL-CVE-2026-6276",
  "aliases": [
    "CVE-2026-6276"
  ],
  "summary": "stale custom cookie host causes cookie leak",
  "modified": "2026-04-29T09:56:23.00Z",
  "database_specific": {
    "package": "curl",
    "affects": "lib",
    "URL": "https://curl.se/docs/CVE-2026-6276.json",
    "www": "https://curl.se/docs/CVE-2026-6276.html",
    "issue": "https://hackerone.com/reports/3671818",
    "CWE": {
      "id": "CWE-346",
      "desc": "Origin Validation Error"
    },
    "last_affected": "8.19.0",
    "severity": "Low"
  },
  "published": "2026-04-29T08:00:00.00Z",
  "affected": [
    {
      "ranges": [
        {
           "type": "SEMVER",
           "events": [
             {"introduced": "7.71.0"},
             {"fixed": "8.20.0"}
           ]
        },
        {
           "type": "GIT",
           "repo": "https://github.com/curl/curl.git",
           "events": [
             {"introduced": "e15e51384a423be31318b3c9c7d612a1aae661fd"},
             {"fixed": "3a19987a87f393d9394fe5acc7643f6c263c92db"}
           ]
        }
      ],
      "versions": [
        "8.19.0", "8.18.0", "8.17.0", "8.16.0", "8.15.0", "8.14.1", "8.14.0", 
        "8.13.0", "8.12.1", "8.12.0", "8.11.1", "8.11.0", "8.10.1", "8.10.0", 
        "8.9.1", "8.9.0", "8.8.0", "8.7.1", "8.7.0", "8.6.0", "8.5.0", 
        "8.4.0", "8.3.0", "8.2.1", "8.2.0", "8.1.2", "8.1.1", "8.1.0", 
        "8.0.1", "8.0.0", "7.88.1", "7.88.0", "7.87.0", "7.86.0", "7.85.0", 
        "7.84.0", "7.83.1", "7.83.0", "7.82.0", "7.81.0", "7.80.0", "7.79.1", 
        "7.79.0", "7.78.0", "7.77.0", "7.76.1", "7.76.0", "7.75.0", "7.74.0", 
        "7.73.0", "7.72.0", "7.71.1", "7.71.0"
      ]
    }
  ],
  "credits": [
    {
      "name": "Muhamad Arga Reksapati",
      "type": "FINDER"
    },
    {
      "name": "Daniel Stenberg",
      "type": "REMEDIATION_DEVELOPER"
    }
  ],
  "details": "Using libcurl, when a custom `Host:` header is first set for an HTTP request\nand a second request is subsequently done using the same *easy handle* but\nwithout the custom `Host:` header set, the second request would use stale\ninformation and pass on cookies meant for the first host in the second\nrequest. Leak them."
}