How severe is CVE-2026-8404?

No CVSS score has been assigned to CVE-2026-8404 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-8404?

CVE-2026-8404 affects the following packages: django (PyPI), django (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-8404?

Update django to 5.2.15 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-8404 is resolved across your whole dependency graph.

How do I detect CVE-2026-8404 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for django. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-8404 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-8404?

O3 pinpoints whether CVE-2026-8404 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-8404 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-8404 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What type of vulnerability is CVE-2026-8404?

CVE-2026-8404 is classified as CWE-178 (CWE-178). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-8404 published, and has it been updated?

CVE-2026-8404 was published on June 3, 2026 and was last updated on August 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

CVE-2026-8404

CVE-2026-8404 is a CWE-178 vulnerability in django. O3 Security confirms whether CVE-2026-8404 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Potential exposure of private data via case-sensitive Cache-Control directives in UpdateCacheMiddleware

Also known asBIT-django-2026-8404GHSA-8cjm-8mp7-r2xfPYSEC-2026-201

Published

Jun 3, 2026

Updated

Aug 7, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Blast Radius

2 pkgs affected

🐍django🐍django

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`django`	all versions	5.2.15
🐍PyPI	`django`	≥ 6.0.0&&< 6.0.6	6.0.6

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for django. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update django to 5.2.15 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-8404 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-8404 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-8404. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is CVE-2026-8404 in your dependencies?

O3 detects CVE-2026-8404 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works