CVE-2026-33033 Potential denial-of-service vulnerability in MultiPartParser via base64-encoded file upload
Remote attackers can degrade Django server performance by submitting multipart uploads with excessive base64 whitespace, requiring an upgrade to patched versions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33033?
CVE-2026-33033 is a medium-severity denial of service vulnerability in Djangoproject Django, published on 7 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
An issue was discovered in 6.0 before 6.0.4, 5.2 before 5.2.13, and 4.2 before 4.2.30. `MultiPartParser` allows remote attackers to degrade performance by submitting multipart uploads with `Content-Transfer-Encoding: base64` including excessive whitespace. 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 Seokchan Yoon for reporting this issue.
Weakness: CWE-407
Which versions are affected by CVE-2026-33033?
8 open source packages ship an affected version, including django and Django. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
django Bitnami | From 4.2.0 | 4.2.30, 5.2.13, 6.0.4 |
django PyPI | From 4.2 | 4.2.30, 5.2.13, 6.0.4 |
django PyPI | From 4.2 | 4.2.30 |
django PyPI | From 5.2 | 5.2.13 |
django PyPI | From 6.0 | 6.0.4 |
Django PyPI | From 4.2 | 4.2.30 |
2 more packages
Django PyPI | From 5.2 | 5.2.13 |
Django PyPI | From 6.0 | 6.0.4 |
Products include Djangoproject Django.
How do I fix CVE-2026-33033?
Upgrade django to a fixed version for your release line: 4.2.30, 5.2.13 or 6.0.4.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-33033 being exploited?
There is no known exploitation of CVE-2026-33033 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Djangoproject Django
- CVE-2026-4277 Privilege abuse in GenericInlineModelAdmin
- CVE-2024-53908 Django SQL injection in HasKey(lhs, rhs) on Oracle
- CVE-2024-42005 Django SQL injection vulnerability
- CVE-2023-31047 Django bypasses validation when using one form field to upload multiple files
- CVE-2022-34265 Django `Trunc()` and `Extract()` database functions vulnerable to SQL Injection
Sources
Also known as BIT-django-2026-33033, CLSA-2026-1787042978, DEBIAN-CVE-2026-33033, ECHO-3bfd-1865-8be2, GHSA-5mf9-h53q-7mhq, MINI-4wvq-5qwr-wp23 and 2 more.