CVE-2026-3902: Django Django Vulnerable To ASGI Header Vulnerability

HIGH
Advisory Identifier: GHSA-mvfq-ggxm-9mc5
Share
CVSS 7.5
CWE-290
Published
Advisory Summary

CVE-2026-3902 is a HIGH (CVSS 7.5) django vulnerable to asgi header vulnerability (CWE-290: Authentication Bypass by Spoofing) affecting Django libraries in the PyPI ecosystem. The issue involves django vulnerable to asgi header spoofing via underscore/hyphen conflation. Remediation is available by upgrading affected packages to version 6.0.4, 5.2.13, 4.2.30.

CVE-2026-3902 at a Glance

CVE Identifier CVE-2026-3902
GHSA Identifier GHSA-mvfq-ggxm-9mc5
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-290: Authentication Bypass by Spoofing
Affected Product Django
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-3902

To remediate this vulnerability, upgrade all affected Django dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Django fixed: 6.0.4 
pip install Django>=6.0.4
Django fixed: 5.2.13 
pip install Django>=5.2.13
Django fixed: 4.2.30 
pip install Django>=4.2.30
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show Django

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-3902, inspect your installed packages using pip:

pip show Django

Analyze the terminal output to locate any version of Django in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.0.4), your application is affected.

Note: The pip show Django command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-290: Authentication Bypass by Spoofing, where this attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. In Django, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2026-3902 Affected Django Versions

3 component(s)
Fixed Versions:
6.0.45.2.134.2.30
Product / Package Ecosystem Affected Versions Fixed Version
Django
pypi/Django
PyPI
≥ 6.0
< 6.0.4
6.0.4
Django
pypi/Django
PyPI
≥ 5.2
< 5.2.13
5.2.13
Django
pypi/Django
PyPI
≥ 4.2
< 4.2.30
4.2.30

References

NVD — CVE-2026-3902 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3902
Django Release RELEASE
https://docs.djangoproject.com/en/dev/releases/security
Django Source Repository REPOSITORY
https://github.com/django/django
Django Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/django/PYSEC-2026-51.yaml
groups.google.com/g/django-announce WEB
https://groups.google.com/g/django-announce
Django Release RELEASE
https://www.djangoproject.com/weblog/2026/apr/07/security-releases

Frequently Asked Questions

What is CVE-2026-3902?
CVE-2026-3902 is a security vulnerability in Django involving Django vulnerable to ASGI header spoofing via underscore/hyphen conflation under CWE-290: Authentication Bypass by Spoofing.
Which Django versions are affected?
Affected versions include releases prior to 6.0.4, 5.2.13, 4.2.30 across affected packages: Django.
What version fixes CVE-2026-3902?
Upgrading to 6.0.4, 5.2.13, 4.2.30 (or the latest patched release for your respective branch) resolves the vulnerability.
Is Django affected?
Yes, Django is affected in releases prior to 6.0.4, 5.2.13, 4.2.30. Upgrade your dependency to 6.0.4, 5.2.13, 4.2.30 or later.
What is the CVSS score of CVE-2026-3902?
CVE-2026-3902 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
What CWE is associated with CVE-2026-3902?
CVE-2026-3902 is classified under CWE-290: Authentication Bypass by Spoofing (This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.).
How can I check PyPI dependencies for CVE-2026-3902?
Run the dependency tree command: 'pip show Django'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mvfq-ggxm-9mc5",
  "modified" : "2026-06-05T17:52:13Z",
  "published" : "2026-04-07T15:30:52Z",
  "aliases" : [ "CVE-2026-3902" ],
  "summary" : "Django vulnerable to ASGI header spoofing via underscore/hyphen conflation",
  "details" : "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.\n\nEarlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected.\nDjango would like to thank Tarek Nakkouch for reporting this issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "Django"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0"
      }, {
        "fixed" : "6.0.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "Django"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.2"
      }, {
        "fixed" : "5.2.13"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "Django"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.2"
      }, {
        "fixed" : "4.2.30"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-3902"
  }, {
    "type" : "WEB",
    "url" : "https://docs.djangoproject.com/en/dev/releases/security"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/django/django"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/django/PYSEC-2026-51.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/g/django-announce"
  }, {
    "type" : "WEB",
    "url" : "https://www.djangoproject.com/weblog/2026/apr/07/security-releases"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-290" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-08T15:39:55Z",
    "nvd_published_at" : "2026-04-07T15:17:46Z"
  }
}