Vulnerability · Published Apr 7, 2026 · Assigned by DSF
CVE-2026-3902ASGI header spoofing via underscore/hyphen conflation
High 7.5
In plain English
A high-severity authentication bypass by spoofing in Django from djangoproject. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | py3-django | 4.2.30-r0 | ALPINE-CVE-2026-3902 |
| Alpine:v3.24 | py3-django | 5.2.13-r0 | ALPINE-CVE-2026-3902 |
| Debian:12 | python-django | no fix listed | DEBIAN-CVE-2026-3902 |
| Debian:13 | python-django | no fix listed | DEBIAN-CVE-2026-3902 |
| Debian:14 | python-django | 3:4.2.30-1 | DEBIAN-CVE-2026-3902 |
| PyPI | django | 6.0.4 | GHSA-mvfq-ggxm-9mc5 |
| PyPI | django | 5.2.13 | GHSA-mvfq-ggxm-9mc5 |
| PyPI | django | 4.2.30 | GHSA-mvfq-ggxm-9mc5 |
| PyPI | django | 4.2.30, 5.2.13, 6.0.4 | PYSEC-2026-51 |
| Ubuntu:22.04:LTS | python-django | 2:3.2.12-2ubuntu1.26 | USN-8154-1 |
| Ubuntu:22.04:LTS | python-django | 2:3.2.12-2ubuntu1.26 | UBUNTU-CVE-2026-3902 |
| Ubuntu:24.04:LTS | python-django | 3:4.2.11-1ubuntu1.15 | USN-8154-1 |
| Ubuntu:24.04:LTS | python-django | 3:4.2.11-1ubuntu1.15 | UBUNTU-CVE-2026-3902 |
| Ubuntu:25.10 | python-django | 3:5.2.4-1ubuntu2.4 | UBUNTU-CVE-2026-3902 |
| Ubuntu:25.10 | python-django | 3:5.2.4-1ubuntu2.4 | USN-8154-1 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| djangoproject | Django | 6.0 – before 6.0.45.2 – before 5.2.134.2 – before 4.2.30 |
Weakness: CWE-290 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
References
- Django security archive vendor-advisory
- Django releases announcements mailing-list
- Django security releases issued: 6.0.4, 5.2.13, and 4.2.30 vendor-advisory