High severity · published Apr 7, 2026
CVE-2026-3902
ASGI header spoofing via underscore/hyphen conflation
7.5
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DJ
Django · djangoproject
6.0 before 6.0.4; 5.2 before 5.2.13; 4.2 before 4.2.30 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3902
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-3902
Patch
https://docs.djangoproject.com/en/dev/releases/security/
Release Notes
https://groups.google.com/g/django-announce
Patch
https://www.djangoproject.com/weblog/2026/apr/07/security-releases/
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