Service degradation via repeated multipart buffer copying
Published Apr 7, 2026 · Updated Apr 7, 2026
Algorithmic complexity in Django 4.2 before 4.2.30, 5.2 before 5.2.13, and 6.0 before 6.0.4 allows remote authenticated users to degrade service. MultiPartParser reads only one to three bytes while aligning base64 data, repeatedly slicing and reinserting the buffered remainder so whitespace-heavy parts cause quadratic memory copying. Reachability requires a multipart file upload using base64 content transfer encoding; a mostly whitespace payload amplifies CPU work and interrupts application service.
Summary
What happened
Algorithmic complexity in Django 4.2 before 4.2.30, 5.2 before 5.2.13, and 6.0 before 6.0.4 allows remote authenticated users to degrade service. MultiPartParser reads only one to three bytes while aligning base64 data, repeatedly slicing and reinserting the buffered remainder so whitespace-heavy parts cause quadratic memory copying. Reachability requires a multipart file upload using base64 content transfer encoding; a mostly whitespace payload amplifies CPU work and interrupts application service.
The record
- CVE
- CVE-2026-33033
- Published
- Apr 7, 2026
- Updated
- Apr 7, 2026
- Vendor
- Django Software Foundation
- Product
- Django
- Classifications
- CWE-407, T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 7, 2026CVE publishedPublication date reported by the CVE source.
- Apr 7, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.2 <4.2.30
- Affected versionversion=5.2 <5.2.13
- Affected versionversion=6.0 <6.0.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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