CVE-2026-3902CWE-290

ASGI header spoofing via underscore/hyphen conflation

High · published April 7, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
45.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00549 · 45.2th percentile
Weakness
CWE-290 · Authentication Bypass by Spoofing
Published
2026-04-07T14:22Z
EPSS history
Timeline
  • 07 APR 14:22Z
    ASGI header spoofing via underscore/hyphen conflation
    cvelistv5