{
  "cveId": "CVE-2026-103502",
  "url": "https://patchblox.com/security/cve/CVE-2026-103502",
  "summary": "CVE-2026-103502 is fixed in erlang-hex on 1 platform by DEBIAN-CVE-2026-103502 (version 2.5.3-2), released October 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "erlang-hex: Improper Certificate Validation vulnerability in hexpm hex_core allows an attacker who can intercept HTTPS connection...",
  "description": "Improper Certificate Validation vulnerability in hexpm hex_core allows an attacker who can intercept HTTPS connections to impersonate hex.pm, repo.hex.pm or any other repository or API server to programs that use hex_core\u0027s default HTTP adapter on Erlang/OTP 24, or on OTP 25 when the operating system\u0027s CA certificates can\u0027t be loaded.  hex_core:default_config/0 selects the built-in hex_http_httpc adapter. For an HTTPS request whose adapter config has no ssl option, hex_http_httpc:http_options/2 builds options that verify the server certificate against public_key:cacerts_get/0. When that call raises, the adapter prints a warning and sends the request without ssl options, so httpc uses the defaults of the ssl application, which before OTP 26 don\u0027t verify the server certificate. public_key:cacerts_get/0 doesn\u0027t exist on OTP 24, so every HTTPS request falls back there, and on OTP 25 it raises when no CA store is found. hex_core versions before 0.11.0 never set ssl options, so they don\u0027t verify the server certificate on OTP 25 and earlier whether or not a CA store is found.  The fallback was intended and documented, but the documentation didn\u0027t make clear that it meant no certificate verification. Since hex_core 0.8.2 the README has warned that the built-in httpc adapter \u0022has insecure default settings\u0022 and recommended other HTTP clients, and the adapter prints \u0022using default ssl options which are insecure\u0022 on every request that falls back. hex_core 0.11.0 added certificate verification with the changelog entry \u0022Use secure SSL defaults for OTP 25\u002B\u0022. Neither the README nor the warning says that the server certificate isn\u0027t verified, the README doesn\u0027t say which OTP versions the warning applies to, and on OTP 25 without CA certificates the warning tells users to upgrade to OTP 25 or later, which they already run. This advisory is published so that users who took those notices as general advice know their HTTPS requests weren\u0027t authenticated.  This issue affects hex_core: from 0.1.0 before 0.20.0.",
  "published": "2026-10-12T14:17:08Z",
  "severity": "",
  "epss": 0.00242,
  "epssPercentile": 0.1541,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "erlang-hex",
      "release": "Debian 14",
      "fixedVersion": "2.5.3-2",
      "fix": "DEBIAN-CVE-2026-103502",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-103502",
      "released": "2026-10-24T13:25:57Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T19:38:12Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}