CVE-2026-53878 — django
Fix: django/django@3a720d0CVE-2026-53878 is a CWE-144 vulnerability in django. A fix is available for django — see the affected versions and patch details below.
Header injection possibility since DomainNameValidator accepted newlines in input
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-53878.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
Real-World Exposure
django🐍djangoReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
An issue was discovered in Django 6.0 before 6.0.7 and 5.2 before 5.2.16.
DomainNameValidator does not prohibit newlines in domain names (unless used via a form field, since CharField strips newlines). If an application uses values with newlines in an HTTP response, header injection can occur. Django itself is unaffected because HttpResponse prohibits newlines in HTTP headers.
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 Bence Nagy for reporting this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | django | all versions | 5.2.16pip install --upgrade 'django==5.2.16' |
| 🐍PyPI | django | ≥ 6.0.0&&< 6.0.7 | 6.0.7pip install --upgrade 'django==6.0.7' |
Affected Products
djangodjangoprojectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for django, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update django to 5.2.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-53878 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This flaw has a Low impact on Red Hat products. A vulnerability in Django's `DomainNameValidator` allows newline characters, which could enable HTTP header injection if validated values are directly used in HTTP response headers outside of Django's standard form handling. However, Django's core HTTP response…
To mitigate this issue, ensure that custom Django applications do not directly place values validated by `DomainNameValidator` into HTTP response headers without further sanitization. Applications should rely on Django's default form handling and `HttpResponse` functionality, which automatically prevent newline injection. If direct header manipulation is unavoidable, implement explicit input sanitization to remove newline characters before constructing HTTP response headers.Source: Red Hat security advisory for CVE-2026-53878 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-53878 in your dependencies?
Find it across PyPI, including transitive dependencies.