{
  "schema_version": "1.5.0",
  "id": "CURL-CVE-2026-19931",
  "aliases": [
    "CVE-2026-19931"
  ],
  "summary": "Negotiate ambient user conn reuse",
  "modified": "2026-09-02T08:08:12.00Z",
  "database_specific": {
    "package": "curl",
    "affects": "both",
    "URL": "https://curl.se/docs/CVE-2026-19931.json",
    "www": "https://curl.se/docs/CVE-2026-19931.html",
    "issue": "https://hackerone.com/reports/3923520",
    "CWE": {
      "id": "CWE-488",
      "desc": "Exposure of Data Element to Wrong Session"
    },
    "last_affected": "8.21.0",
    "severity": "Medium"
  },
  "published": "2026-09-02T08:00:00.00Z",
  "affected": [
    {
      "ranges": [
        {
           "type": "SEMVER",
           "events": [
             {"introduced": "7.64.1"},
             {"fixed": "8.22.0"}
           ]
        },
        {
           "type": "GIT",
           "repo": "https://github.com/curl/curl.git",
           "events": [
             {"introduced": "6c6035532383e300c712e4c1cd9fdd749ed5cf59"},
             {"fixed": "7103a93b05bc69ea98ed9d05d02fa9eeba533f2f"}
           ]
        }
      ],
      "versions": [
        "8.21.0", "8.20.0", "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", "7.70.0", 
        "7.69.1", "7.69.0", "7.68.0", "7.67.0", "7.66.0", "7.65.3", "7.65.2", 
        "7.65.1", "7.65.0", "7.64.1"
      ]
    }
  ],
  "credits": [
    {
      "name": "Martin Dukek",
      "type": "FINDER"
    },
    {
      "name": "Stefan Eissing",
      "type": "REMEDIATION_DEVELOPER"
    }
  ],
  "details": "A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given\nhostname using Negotiate authentication, when the initial request is done\nusing empty credentials. This can make user B's request get sent over user A's\npreviously authenticated connection."
}