{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.35"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "17a30c10a8af0f1f65ab19860f413716fb6cde76"
            }
          ],
          "repo": "https://github.com/plack/Plack-Middleware-Session",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1fbfbb355e34e7f4b3906f66cf958cedadd2b9be"
            }
          ],
          "repo": "https://github.com/plack/plack-middleware-session",
          "type": "GIT"
        }
      ]
    }
  ],
  "details": "Plack-Middleware-Session before version 0.35 for Perl generates session ids insecurely.\n\nThe default session id generator returns a SHA-1 hash seeded with the built-in rand function, the epoch time, and the PID. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage.\n\nPredicable session ids could allow an attacker to gain access to systems.",
  "id": "CVE-2025-40923",
  "modified": "2026-04-01T23:08:42.268284387Z",
  "published": "2025-07-16T13:15:23.997Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2025/07/16/4"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/MIYAGAWA/Plack-Middleware-Session-0.34/source/lib/Plack/Session/State.pm#L22"
    },
    {
      "type": "WEB",
      "url": "https://security.metacpan.org/docs/guides/random-data-for-security.html"
    },
    {
      "type": "FIX",
      "url": "https://github.com/plack/Plack-Middleware-Session/commit/1fbfbb355e34e7f4b3906f66cf958cedadd2b9be.patch"
    },
    {
      "type": "FIX",
      "url": "https://github.com/plack/Plack-Middleware-Session/pull/52"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    }
  ]
}