What’s Vulnerable › Vulnerabilities

CVE-2026-33033: Potential denial-of-service vulnerability in MultiPartParser via base64-encoded file upload

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-07 · updated 2026-10-26
• Weakness: CWE-407

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.

Affected products

• Django: from 4.2 before 4.2.30; from 5.2 before 5.2.13; from 6.0 before 6.0.4 — fixed in 4.2.30, 5.2.13, 6.0.4

How to fix

Upgrade to a fixed version: Django 4.2.30, 5.2.13, 6.0.4. Check the vendor advisory for mitigations.

References

• https://docs.djangoproject.com/en/dev/releases/security/
• https://groups.google.com/g/django-announce
• https://www.djangoproject.com/weblog/2026/apr/07/security-releases/

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