CVE-2026-3902

ASGI header spoofing via underscore/hyphen conflation

State: Published
Severity: 7.5 High
Published: Apr 7, 2026
Updated: Apr 7, 2026
Reserved: Mar 10, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N	CISA-ADP

Weaknesses

CWE-290 Authentication Bypass by Spoofing

Affected Products

Product	Versions
Djangodjangoproject	6.0 to before 6.0.4Affected 6.0.4Not affected 5.2 to before 5.2.13Affected 5.2.13Not affected 4.2 to before 4.2.30Affected 4.2.30Not affected

References

Django security archivevendor-advisory
Django releases announcementsmailing-list
Django security releases issued: 6.0.4, 5.2.13, and 4.2.30vendor-advisory

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