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CVE-2026-3902

ASGI header spoofing via underscore/hyphen conflation

No known exploitation. EPSS puts it in the 39th percentile. Fixed versions are out.

CVSS 3.17.5HighEPSS percentile39th0.4% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix5 products3 fixed builds listed below
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OpenVAS · 17 checks

e.g. OID 1.3.6.1.4.1.25623.1.0.138069

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Published Updated Sources: CVE.org, NVD, BDU

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • djangoproject DjangoAffected: ≥ 6.0, < 6.0.4Upgrade to: 6.0.4Affected: ≥ 5.2, < 5.2.13Upgrade to: 5.2.13Affected: ≥ 4.2, < 4.2.30Upgrade to: 4.2.30Stated by: CVE record
  • Canonical Ltd. UbuntuAffected: 14.04 LTSUpgrade to: not statedStated by: BDU
  • ООО «Ред Софт» РЕД ОСAffected: 7.3Upgrade to: not statedStated by: BDU
  • Red Hat Inc. Red Hat SatelliteAffected: 6Upgrade to: not statedStated by: BDU
  • Red Hat Inc. DiscoveryAffected: 2Upgrade to: not statedStated by: BDU

Versions as the sources state them. 2 more products have version data. Full version matrix after sign-in

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS39th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.4% chance of exploitation activity in the next 30 days, which ranks it in the 39th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

8 events over 202 days, from the signal feeds we watch.

  1. Patch availablerecord updated
  2. OpenVAS check added
  3. Patch availablerecord updated
  4. Publishedweakness classified, att&ck mapped

Affected products

And 1 more affected product. See all after sign-in

Scale

How widely the affected products are used. This is not a count of vulnerable hosts.

Estimate Public sources, each figure dated. How much of it is already patched is not known.

Django

Library

  • 41.1Mdownloads / month

    PyPI downloads, last 30 days (pypistats, mirrors excluded).

    PyPI ↗ · as of 2 Nov 2026 · High confidence

Version split: unknown. No public source for this product.

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Scored 7.5 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability NoneNo availability impact

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 6 more references. See all after sign-in

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