Denial of service via quadratic header parsing
Published Oct 6, 2026 · Updated Oct 6, 2026
Denial of service in Django 5.2 before 5.2.18 allows remote attackers to exhaust CPU via crafted HTTP request headers. In django.utils.http.parse_header_parameters(), repeated quote counting while locating separators inside a quoted parameter makes parsing quadratic. Django 6.0 before 6.0.9 and 6.1 before 6.1.2 share the flaw; exposure requires a request path that parses attacker-controlled headers, such as Accept-based content negotiation.
Summary
What happened
Denial of service in Django 5.2 before 5.2.18 allows remote attackers to exhaust CPU via crafted HTTP request headers. In django.utils.http.parse_header_parameters(), repeated quote counting while locating separators inside a quoted parameter makes parsing quadratic. Django 6.0 before 6.0.9 and 6.1 before 6.1.2 share the flaw; exposure requires a request path that parses attacker-controlled headers, such as Accept-based content negotiation.
The record
- CVE
- CVE-2026-84429
- Published
- Oct 6, 2026
- Updated
- Oct 6, 2026
- Vendor
- Django Software Foundation
- Product
- Django
- Classifications
- CWE-407, CAPEC-130, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 6, 2026CVE publishedPublication date reported by the CVE source.
- Oct 6, 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=5.2 <5.2.18
- Affected versionversion=6.0 <6.0.9
- Affected versionversion=6.1 <6.1.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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