ASGI header spoofing via underscore/hyphen conflation

{
  "id": "6656669bbc366231200c9f1ff16c9d789919d7ba2d5146fd872e2c9429f1d0c0",
  "url": "https://osv.dev/vulnerability/CVE-2026-3902",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ASGI header spoofing via underscore/hyphen conflation",
    "summary": "An issue was discovered in 6.0 before 6.0.4, 5.2 before 5.2.13, and 4.2 before 4.2.30. `ASGIRequest` allows a remote attacker to spoof headers by exploiting an ambiguous mapping of two header variants (with hyphens or with underscores) to a single version with underscores. Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected. Django would like to thank Tarek Nakkouch for reporting this issue.",
    "evidence": "osv:CVE-2026-3902",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-3902",
      "aliases": [
        "BIT-django-2026-3902",
        "CVE-2026-3902",
        "GHSA-mvfq-ggxm-9mc5",
        "PYSEC-2026-51"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/django/django",
              "type": "GIT",
              "events": [
                {
                  "introduced": "97aa3b7f08f51669e118f3af5ca91026e39664c3"
                },
                {
                  "fixed": "3396992e837d5146270ea8112bb622c83fa4a919"
                },
                {
                  "introduced": "9e7cc2b628fe8fd3895986af9b7fc9525034c1b0"
                },
                {
                  "fixed": "7d831a9eeb88a6bf484af7b56fe29596bdbf09a6"
                },
                {
                  "introduced": "36b5f39d9372147f0e758f590e35ee2b2bc317dd"
                },
                {
                  "fixed": "141e791f48592011b0f38fb30d44291e3ce74ee0"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "4.2"
                      },
                      {
                        "fixed": "4.2.30"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "5.2"
                      },
                      {
                        "fixed": "5.2.13"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "6.0"
                      },
                      {
                        "fixed": "6.0.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "5.2.12",
            "6.0.3",
            "5.2.11",
            "6.0.2",
            "6.0.1",
            "5.2.10",
            "6.0",
            "5.2.9",
            "5.2.8",
            "5.2.7",
            "5.2.6",
            "5.2.5",
            "5.2.4",
            "5.2.3",
            "5.2.2",
            "5.2.1",
            "5.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-3902.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:40.054321268Z",
      "provider": "osv",
      "references": [
        "https://github.com/django/django/",
        "https://docs.djangoproject.com/en/dev/releases/security/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3902.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-3902",
        "https://www.djangoproject.com/weblog/2026/apr/07/security-releases/",
        "https://pypi.org/project/Django/",
        "https://groups.google.com/g/django-announce"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-290"
        ],
        "cna_assigner": "DSF",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3902.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-3902",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 507732,
  "published_at": "2026-04-07T14:22:07.19+00:00"
}