What’s Vulnerable › Vulnerabilities

CVE-2026-48587: Potential exposure of private data via whitespace padding in Vary header

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-03 · updated 2026-07-21
• Weakness: CWE-1023

Description

An issue was discovered in Django 5.2 before 5.2.15 and 6.0 before 6.0.6. `django.utils.cache.has_vary_header()` in Django does not strip leading or trailing whitespace from `Vary` response header values before comparison, which allows remote attackers to read cached responses via requests to URLs whose responses contain whitespace-padded Vary header values. 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 Navid Rezazadeh for reporting this issue.

Affected products

• Django: from 5.2 before 5.2.15; from 6.0 before 6.0.6 — fixed in 5.2.15, 6.0.6
• Pypi Django: before 5.2.15; from 6.0.0 before 6.0.6; 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.1, 1.1.1 (+422) — fixed in 5.2.15, 6.0.6

How to fix

Upgrade to a fixed version: Django 5.2.15, 6.0.6; Pypi Django 5.2.15, 6.0.6. 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/jun/03/security-releases/

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