CVE-2026-3902: 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

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HIGH 7.5REMOTEUPGRADE

CVE-2026-3902 is a high-severity flaw (CVSS 7.5) affecting django. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 i

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 62%)
CISA exploited list	No
Weakness	CWE-290
Published	2026-04-07
Last modified	2026-10-26

Publisher (CNA): Django Software Foundation · Vendor: djangoproject

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-07 15:17 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

djangoproject django UPGRADE

Affected: >= 4.2 and < 4.2.30 · >= 5.2 and < 5.2.13 · >= 6.0 and < 6.0.4

Fixed in: 4.2.30, 5.2.13, 6.0.4

Safe to downgrade to: a release before 4.2

1. Check installed version

apt-cache policy django || rpm -q django || django --version

2. UPGRADE to 4.2.30 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade django

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade django

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 4.2 (Debian / Ubuntu)

apt-cache madison django sudo apt install django=<VERSION_BEFORE_4.2> sudo apt-mark hold django

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list django sudo dnf downgrade django-<VERSION_BEFORE_4.2> sudo dnf versionlock add django

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-3902?

django: upgrade to 4.2.30, 5.2.13, 6.0.4. Exact commands for each OS are on this page.

Is CVE-2026-3902 being exploited?

CVE-2026-3902 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-3902 affect?

CVE-2026-3902 affects django. Severity is high (CVSS 7.5). 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

How urgent is CVE-2026-3902?

Priority 41/100. High severity; Remotely exploitable, no login, no user action

Software pages

Django vulnerabilities

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References

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