Django Channels leakage of session identifiers using legacy AsgiHandler
Django Channels 3.x before 3.0.3 allows remote attackers to obtain sensitive information from a different request scope. The legacy channels.http.AsgiHandler class, used for handling HTTP type requests in an ASGI environment prior to Django 3.0, did not correctly separate request scopes in Channels 3.0. In many cases this would result in a crash but, with correct timing, responses could be sent to the wrong client, resulting in potential leakage of session identifiers and other sensitive data. Note that this affects only the legacy Channels provided class, and not Django's similar ASGIHandler, available from Django 3.0.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | channels | >= 3.0.0, < 3.0.3 | 3.0.3 |
References
- https://github.com/django/channels/releases
- https://channels.readthedocs.io/en/stable/releases/3.0.3.html
- https://channels.readthedocs.io/en/stable/releases/index.html
- https://github.com/advisories/GHSA-v542-8q9x-cffc
- https://nvd.nist.gov/vuln/detail/CVE-2020-35681
- https://github.com/django/channels/commit/e85874d9630474986a6937430eac52db79a2a022
- https://github.com/django/channels
- https://github.com/pypa/advisory-database/tree/main/vulns/channels/PYSEC-2021-113.yaml
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H- Weakness (CWE)
CWE-200- Platform
- Python (PyPI)
- Package
channels- Disclosed
- 22.02.2021
- Updated
- 11.10.2026 11:19
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2021-113 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-v542-8q9x-cffc - CC BY 4.0
Vulnerability history: channels
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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