{
  "schema_version": "1.5.0",
  "id": "CURL-CVE-2026-4873",
  "aliases": [
    "CVE-2026-4873"
  ],
  "summary": "connection reuse ignores TLS requirement",
  "modified": "2026-04-29T09:56:23.00Z",
  "database_specific": {
    "package": "curl",
    "affects": "both",
    "URL": "https://curl.se/docs/CVE-2026-4873.json",
    "www": "https://curl.se/docs/CVE-2026-4873.html",
    "issue": "https://hackerone.com/reports/3621851",
    "CWE": {
      "id": "CWE-319",
      "desc": "Cleartext Transmission of Sensitive Information"
    },
    "last_affected": "8.19.0",
    "severity": "Low"
  },
  "published": "2026-04-29T08:00:00.00Z",
  "affected": [
    {
      "ranges": [
        {
           "type": "SEMVER",
           "events": [
             {"introduced": "7.20.0"},
             {"fixed": "8.20.0"}
           ]
        },
        {
           "type": "GIT",
           "repo": "https://github.com/curl/curl.git",
           "events": [
             {"introduced": "ec3bb8f727405642a471b4b1b9eb0118fc003104"},
             {"fixed": "507e7be573b0a76fca597b75ff7cb27a66e7d865"}
           ]
        }
      ],
      "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", "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", "7.64.0", "7.63.0", "7.62.0", "7.61.1", "7.61.0", "7.60.0", 
        "7.59.0", "7.58.0", "7.57.0", "7.56.1", "7.56.0", "7.55.1", "7.55.0", 
        "7.54.1", "7.54.0", "7.53.1", "7.53.0", "7.52.1", "7.52.0", "7.51.0", 
        "7.50.3", "7.50.2", "7.50.1", "7.50.0", "7.49.1", "7.49.0", "7.48.0", 
        "7.47.1", "7.47.0", "7.46.0", "7.45.0", "7.44.0", "7.43.0", "7.42.1", 
        "7.42.0", "7.41.0", "7.40.0", "7.39.0", "7.38.0", "7.37.1", "7.37.0", 
        "7.36.0", "7.35.0", "7.34.0", "7.33.0", "7.32.0", "7.31.0", "7.30.0", 
        "7.29.0", "7.28.1", "7.28.0", "7.27.0", "7.26.0", "7.25.0", "7.24.0", 
        "7.23.1", "7.23.0", "7.22.0", "7.21.7", "7.21.6", "7.21.5", "7.21.4", 
        "7.21.3", "7.21.2", "7.21.1", "7.21.0", "7.20.1", "7.20.0"
      ]
    }
  ],
  "credits": [
    {
      "name": "Arkadi Vainbrand",
      "type": "FINDER"
    },
    {
      "name": "Daniel Stenberg",
      "type": "REMEDIATION_DEVELOPER"
    }
  ],
  "details": "A vulnerability exists where a connection requiring TLS incorrectly reuses an\nexisting unencrypted connection from the same connection pool. If an initial\ntransfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request\nto that same host bypasses the TLS requirement and instead transmit data\nunencrypted."
}