CVE-2026-8404: Django UpdateCacheMiddleware May Disclose Cached Responses Vulnerability

LOW
Advisory Identifier: GHSA-8cjm-8mp7-r2xf
Share
CVSS 3.1
CWE-178
Published
Advisory Summary

CVE-2026-8404 is a LOW (CVSS 3.1) updatecachemiddleware may disclose cached responses vulnerability (CWE-178: Improper Handling of Case Sensitivity) affecting Django libraries in the PyPI ecosystem. The issue involves updatecachemiddleware may disclose cached responses due to case-sensitive cache-control handling. Remediation is available by upgrading affected packages to version 5.2.15, 6.0.6.

CVE-2026-8404 at a Glance

CVE Identifier CVE-2026-8404
GHSA Identifier GHSA-8cjm-8mp7-r2xf
Severity LOW
CVSS v3.1 Base Score 3.1
CWE Classification CWE-178: Improper Handling of Case Sensitivity
Affected Product Django
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 3.1

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

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

How to Fix CVE-2026-8404

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: 5.2.15 
pip install django>=5.2.15
django fixed: 6.0.6 
pip install django>=6.0.6
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-2026-8404, 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 5.2.15), 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-178: Improper Handling of Case Sensitivity, where the product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results. 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 Django 5.2 before 5.2.15 and 6.0 before 6.0.6. `django.middleware.cache.UpdateCacheMiddleware` in Django does not match `Cache-Control` response directives case-insensitively, which allows remote attackers to read responses that were incorrectly cached because their `Cache-Control` directives used uppercase or mixed-case values. 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 Ahmed Badawe for reporting this issue.

CVE-2026-8404 Affected Django Versions

2 component(s)
Fixed Versions:
5.2.156.0.6
Product / Package Ecosystem Affected Versions Fixed Version
django
pypi/django
PyPI
< 5.2.15
5.2.15
django
pypi/django
PyPI
≥ 6.0.0
< 6.0.6
6.0.6

References

NVD — CVE-2026-8404 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-8404
Security Fix Commit FIX COMMIT
https://github.com/django/django/commit/366d9ae6e8d1469c04e9ebdc1bcd098fc14a3b1e
Security Fix Commit FIX COMMIT
https://github.com/django/django/commit/b4330259ffbe1a031ed14daab1f35697460f10f2
Security Fix Commit FIX COMMIT
https://github.com/django/django/commit/d618d7ae4fec727d5b582bd24f803c28d17bf7cd
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-2026-201.yaml
groups.google.com/g/django-announce WEB
https://groups.google.com/g/django-announce
Django Release RELEASE
https://www.djangoproject.com/weblog/2026/jun/03/security-releases

Frequently Asked Questions

What is CVE-2026-8404?
CVE-2026-8404 is a security vulnerability in Django involving UpdateCacheMiddleware may disclose cached responses due to case-sensitive Cache-Control handling under CWE-178: Improper Handling of Case Sensitivity.
Which Django versions are affected?
Affected versions include releases prior to 5.2.15, 6.0.6 across affected packages: django.
What version fixes CVE-2026-8404?
Upgrading to 5.2.15, 6.0.6 (or the latest patched release for your respective branch) resolves the vulnerability.
Is django affected?
Yes, django is affected in releases prior to 5.2.15, 6.0.6. Upgrade your dependency to 5.2.15, 6.0.6 or later.
What is the CVSS score of CVE-2026-8404?
CVE-2026-8404 has a CVSS v3.1 base score of 3.1 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2026-8404?
CVE-2026-8404 is classified under CWE-178: Improper Handling of Case Sensitivity (The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.).
How can I check PyPI dependencies for CVE-2026-8404?
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-8cjm-8mp7-r2xf",
  "modified" : "2026-08-07T20:03:57Z",
  "published" : "2026-06-03T15:30:43Z",
  "aliases" : [ "CVE-2026-8404" ],
  "summary" : "Django: UpdateCacheMiddleware may disclose cached responses due to case-sensitive Cache-Control handling",
  "details" : "An issue was discovered in Django 5.2 before 5.2.15 and 6.0 before 6.0.6.\n`django.middleware.cache.UpdateCacheMiddleware` in Django does not match `Cache-Control` response directives case-insensitively, which allows remote attackers to read responses that were incorrectly cached because their `Cache-Control` directives used uppercase or mixed-case values.\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 Ahmed Badawe for reporting this issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "django"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.2.15"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "django"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0.0"
      }, {
        "fixed" : "6.0.6"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-8404"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/django/django/commit/366d9ae6e8d1469c04e9ebdc1bcd098fc14a3b1e"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/django/django/commit/b4330259ffbe1a031ed14daab1f35697460f10f2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/django/django/commit/d618d7ae4fec727d5b582bd24f803c28d17bf7cd"
  }, {
    "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-2026-201.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/g/django-announce"
  }, {
    "type" : "WEB",
    "url" : "https://www.djangoproject.com/weblog/2026/jun/03/security-releases"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-178" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-07T20:03:57Z",
    "nvd_published_at" : "2026-06-03T14:16:47Z"
  }
}