Service interruption via Truncator regex backtracking
Published Nov 3, 2023 · Updated Nov 4, 2025
Denial of service in Django 3.2 before 3.2.22, 4.1 before 4.1.12, and 4.2 before 4.2.6 allows attackers to interrupt service via long HTML. Truncator chars() and words() with html=True run regular expressions with linear backtracking over very long, potentially malformed HTML instead of bounding the input. Exposure requires an application to pass attacker-controlled text to these APIs or their template filters, where expensive evaluation can occupy workers and interrupt service.
Summary
What happened
Denial of service in Django 3.2 before 3.2.22, 4.1 before 4.1.12, and 4.2 before 4.2.6 allows attackers to interrupt service via long HTML. Truncator chars() and words() with html=True run regular expressions with linear backtracking over very long, potentially malformed HTML instead of bounding the input. Exposure requires an application to pass attacker-controlled text to these APIs or their template filters, where expensive evaluation can occupy workers and interrupt service.
The record
- CVE
- CVE-2023-43665
- Published
- Nov 3, 2023
- Updated
- Nov 4, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-400, CWE-1284, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 3, 2023CVE publishedPublication date reported by the CVE source.
- Nov 4, 2025Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
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