djust has Cross-Site Request Forgery on the Server-Sent-Events transport: a cross-origin page can drive a victim-authenticated SSE session
Impact
The SSE client→server POST endpoints are @csrf_exempt and the SSE GET stream endpoint had no Origin check, so a cross-origin page could drive a victim-cookie-authenticated SSE session: force the victim's browser to GET the stream URL (which creates and mounts a LiveView as the victim) and POST to the message endpoint with credentials: include to fire state-changing event handlers as the victim. The URL session_id is client-chosen (validated only for UUID format), so it is not a CSRF token, and a JSON body sent as text/plain is a CORS simple request with no preflight.
Patches
Fixed in djust 1.0.7. All three SSE endpoints validate the request Origin against ALLOWED_HOSTS (mirroring the WebSocket CSWSH defense) and reject cross-origin requests with 403; the POST endpoints additionally require Content-Type: application/json (415 otherwise), closing the text/plain simple-request bypass.
Workarounds
Disable the SSE transport, or front it with a proxy that enforces an Origin allowlist.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | djust | < 1.0.7 | 1.0.7 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N- Weakness (CWE)
CWE-352- Platform
- Python (PyPI)
- Package
djust- Disclosed
- 16.09.2026
- Updated
- 11.10.2026 15:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-4044 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-pg97-jvmf-qfvc - CC BY 4.0
Vulnerability history: djust
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 15
- First → latest
- 08.2026 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 11
- Medium 3
Disclosures per year
- 2026: 15
-
djust has Cross-Site Request Forgery on the Server-Sent-Events transport: a cross-origin page can drive a victim-authenticated SSE session this entry
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