CVE-2026-3902

ASGI header spoofing via underscore/hyphen conflation

Published Apr 7, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-mvfq-ggxm-9mc5 Django vulnerable to ASGI header spoofing via underscore/hyphen conflation
Ubuntu USN Ubuntu USN USN-8154-1 Django vulnerabilities
History
Type Values Removed Values Added
CPEs cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Djangoproject
Djangoproject django
Vendors & Products Djangoproject
Djangoproject django
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title ASGI header spoofing via underscore/hyphen conflation
Weaknesses CWE-290
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
DSF
Published
Updated
Apr 7, 2026, 4:14 PM
Reserved
Mar 10, 2026, 6:33 PM
Status
Analyzed
Published
Apr 7, 2026, 3:17 PM
Modified
Oct 26, 2026, 9:10 PM
Severity
Moderate
Public date
Apr 7, 2026, 2:22 PM