CVE-2023-23969: Django contains Uncontrolled Resource Consumption via cached header

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 47.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-02-01 · updated 2026-06-17
Weakness: CWE-770

Description

In Django 3.2 before 3.2.17, 4.0 before 4.0.9, and 4.1 before 4.1.6, the parsed values of Accept-Language headers are cached in order to avoid repetitive parsing. This leads to a potential denial-of-service vector via excessive memory usage if the raw value of Accept-Language headers is very large.

Affected products

Debian Linux: 10.0
Django: from 3.2 before 3.2.17; from 4.0 before 4.0.9; from 4.1 before 4.1.6 — fixed in 3.2.17, 4.0.9, 4.1.6
Pypi Django: from 3.2 before 3.2.17; from 4.0 before 4.0.9; from 4.1 before 4.1.6; 3.2, 3.2.1, 3.2.10, 3.2.11, 3.2.12, 3.2.13 (+26) — fixed in 3.2.17, 4.0.9, 4.1.6

How to fix

Upgrade to a fixed version: Django 3.2.17, 4.0.9, 4.1.6; Pypi Django 3.2.17, 4.0.9, 4.1.6. Check the vendor advisory for mitigations.

References

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