{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "1.0.0"
              },
              {
                "fixed": "1.11.0"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "124d697c3c604aca9122332a4ea789561b925f2e"
            },
            {
              "fixed": "e62619895d0d2584d7ffa57d43ef6f72437dfaff"
            },
            {
              "fixed": "45feea20dea8af7ffd7245271107b695c040e667"
            }
          ],
          "repo": "https://github.com/mtrudel/bandit",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-375f-4r2h-f99j"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-807"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39807.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "ff2f829326cd5dcf7335939aef9775269d881e28"
          },
          {
            "fixed": "45feea20dea8af7ffd7245271107b695c040e667"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Reliance on Untrusted Inputs in a Security Decision vulnerability in mtrudel bandit allows unauthenticated transport-state spoofing on plaintext HTTP connections.\n\n'Elixir.Bandit.Pipeline':determine_scheme/2 in lib/bandit/pipeline.ex returns the client-supplied URI scheme verbatim, ignoring the transport's secure? flag. HTTP/1.1 absolute-form request targets (e.g. GET https://victim/path HTTP/1.1) and the HTTP/2 :scheme pseudo-header are both attacker-controlled strings that flow through this function. Over a plaintext TCP connection, a client can declare https and Bandit will set conn.scheme = :https even though no TLS was negotiated.\n\nDownstream Plug consumers that branch on conn.scheme are silently misled: Plug.SSL's already-secure branch skips its HTTP→HTTPS redirect, cookies emitted with secure: true are sent over plaintext, audit logs record requests as having arrived over HTTPS, and CSRF/SameSite gating may make incorrect decisions.\n\nThis issue affects bandit: from 1.0.0 before 1.11.0.",
  "id": "CVE-2026-39807",
  "modified": "2026-07-08T05:38:01.784280105Z",
  "published": "2026-05-01T20:34:22.832Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-39807.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-39807"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39807.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-375f-4r2h-f99j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-39807"
    },
    {
      "type": "FIX",
      "url": "https://github.com/mtrudel/bandit/commit/45feea20dea8af7ffd7245271107b695c040e667"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mtrudel/bandit"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Client-supplied URI scheme trusted without transport verification in bandit"
}