`aiohttp` Open Redirect vulnerability (`normalize_path_middleware` middleware)
Impact
Open redirect vulnerability — a maliciously crafted link to an aiohttp-based web-server could redirect the browser to a different website.
It is caused by a bug in the aiohttp.web_middlewares.normalize_path_middleware middleware.
Patches
This security problem has been fixed in v3.7.4. Upgrade your dependency as follows:
pip install aiohttp >= 3.7.4
Workarounds
If upgrading is not an option for you, a workaround can be to avoid using aiohttp.web_middlewares.normalize_path_middleware in your applications.
References
For more information
If you have any questions or comments about this advisory:
- Open an issue in the aiohttp repo
- Email us at wk+aio-libs-security@sydorenko.org.ua and/or andrew.svetlov+aio-libs-security@gmail.com
Credit: Jelmer Vernooij and Beast Glatisant.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | aiohttp | < 3.7.4 | 3.7.4 |
References
- https://github.com/aio-libs/aiohttp/commit/2545222a3853e31ace15d87ae0e2effb7da0c96b
- https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst#374-2021-02-25
- https://pypi.org/project/aiohttp/
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-v6wp-4m6f-gcjg
- https://www.debian.org/security/2021/dsa-4864
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JN3V7CZJRT4QFCVXB6LDPCJH7NAOFCA5/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FU7ENI54JNEK3PHEFGCE46DGMFNTVU6L/
- https://nvd.nist.gov/vuln/detail/CVE-2021-21330
- https://github.com/aio-libs/aiohttp
- https://github.com/pypa/advisory-database/tree/main/vulns/aiohttp/PYSEC-2021-76.yaml
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FU7ENI54JNEK3PHEFGCE46DGMFNTVU6L
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JN3V7CZJRT4QFCVXB6LDPCJH7NAOFCA5
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FU7ENI54JNEK3PHEFGCE46DGMFNTVU6L
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JN3V7CZJRT4QFCVXB6LDPCJH7NAOFCA5
- https://pypi.org/project/aiohttp
- https://security.gentoo.org/glsa/202208-19
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N- Weakness (CWE)
CWE-601- Platform
- Python (PyPI)
- Package
aiohttp- Disclosed
- 26.02.2021
- Updated
- 11.10.2026 13:19
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2021-76 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-v6wp-4m6f-gcjg - CC BY 4.0
Vulnerability history: aiohttp
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
- 55
- First → latest
- 02.2021 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 7
- Medium 29
- Low 19
Disclosures per year
- 2021: 1
- 2022: 0
- 2023: 6
- 2024: 7
- 2025: 1
- 2026: 40
-
`aiohttp` Open Redirect vulnerability (`normalize_path_middleware` middleware) this entry
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