CVE-2026-3902 ASGI header spoofing via underscore/hyphen conflation
Remote attackers can spoof HTTP headers in Django applications by exploiting ambiguous underscore/hyphen mapping in ASGI requests.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-3902?
CVE-2026-3902 is a high-severity vulnerability in Djangoproject Django, published on 7 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An issue was discovered in 6.0 before 6.0.4, 5.2 before 5.2.13, and 4.2 before 4.2.30. `ASGIRequest` allows a remote attacker to spoof headers by exploiting an ambiguous mapping of two header variants (with hyphens or with underscores) to a single version with underscores. 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 Tarek Nakkouch for reporting this issue.
Weakness: CWE-290
Which versions are affected by CVE-2026-3902?
8 open source packages ship an affected version, including django and Django. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
django Bitnami | From 4.2.0 | 4.2.30, 5.2.13, 6.0.4 |
django PyPI | From 4.2 | 4.2.30, 5.2.13, 6.0.4 |
django PyPI | From 4.2 | 4.2.30 |
django PyPI | From 5.2 | 5.2.13 |
django PyPI | From 6.0 | 6.0.4 |
Django PyPI | From 4.2 | 4.2.30 |
2 more packages
Django PyPI | From 5.2 | 5.2.13 |
Django PyPI | From 6.0 | 6.0.4 |
Products include Djangoproject Django.
How do I fix CVE-2026-3902?
Upgrade django to a fixed version for your release line: 4.2.30, 5.2.13 or 6.0.4.
Is CVE-2026-3902 being exploited?
There is no known exploitation of CVE-2026-3902 in the wild and no public exploit code.
Other vulnerabilities in Djangoproject Django
- CVE-2026-4277 Privilege abuse in GenericInlineModelAdmin
- CVE-2024-53908 Django SQL injection in HasKey(lhs, rhs) on Oracle
- CVE-2024-42005 Django SQL injection vulnerability
- CVE-2023-31047 Django bypasses validation when using one form field to upload multiple files
- CVE-2022-34265 Django `Trunc()` and `Extract()` database functions vulnerable to SQL Injection
Sources
Also known as BIT-django-2026-3902, DEBIAN-CVE-2026-3902, ECHO-f4ca-f938-4210, GHSA-mvfq-ggxm-9mc5, MINI-wxh4-6949-ghf6, PYSEC-2026-51 and 1 more.