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Fencer Vulns
low 3.1

CVE-2021-21330 json

Open redirect vulnerability in aiohttp

published 2021-02-26 5 y ago modified 2026-07-08 4 mo ago also GHSA-v6wp-4m6f-gcjg , PYSEC-2021-76 , EUVD-2021-0003

cvss
3.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. In aiohttp before version 3.7.4 there is an 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. This security problem has been fixed in 3.7.4. Upgrade your dependency using pip as follows "pip install aiohttp >= 3.7.4". If upgrading is not an option for you, a workaround can be to avoid using `aiohttp.web_middlewares.normalize_path_middleware` in your applications.

Patch / fix

  • pypi aiohttp 3.7.4
  • aiohttp aiohttp 3.7.4
  • python-aiohttp Debian 14, Debian 13, Debian 12 3.7.4-1

debian advisories DEBIAN-CVE-2021-21330

  • python-aiohttp Ubuntu Pro 18.04 LTS 3.0.1-1ubuntu0.1~esm1
  • python-aiohttp Ubuntu Pro 20.04 LTS 3.6.2-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2021-21330

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • foreman satellite capsule 6.10, satellite 6.10 2.5.2.17-2.el7sat
  • candlepin satellite 6.10 4.0.9-1.el7sat
  • satellite satellite capsule 6.10, satellite 6.10 6.10.0-3.el7sat
  • python-ecdsa satellite capsule 6.10, satellite 6.10 0.13.3-2.el7pc
  • python-pyyaml satellite capsule 6.10, satellite 6.10 5.4.1-1.el7pc
  • python3-ecdsa satellite capsule 6.10, satellite 6.10 0.13.3-2.el7pc
  • python-aiohttp satellite capsule 6.10, satellite 6.10 3.7.4-1.el7pc
  • python-urllib3 satellite capsule 6.10, satellite 6.10 1.26.5-1.el7pc

red hat advisories RHSA-2021:4702

  • python-typing_extensions SLE Module for Public Cloud 15 SP3, SLE Module for Public Cloud 15 SP2, SLE Module for Public Cloud 15 SP1 3.10.0.0-150100.3.3.1
  • python-typing_extensions SLE Module for Server Applications 15 SP4, openSUSE Leap 15.4 3.10.0.0-150400.3.2.1
  • python-aiohttp SLE Module for Public Cloud 15 SP4, SLE Module for Public Cloud 15 SP3, SLE Module for Public Cloud 15 SP2 +3 more 3.6.0-150100.3.9.1
  • python-aiohttp SLE Module for Public Cloud 15 SP2, SLE Module for Public Cloud 15 SP1 3.4.4-3.6.1

suse advisories SUSE-RU-2022:3275-1SUSE-SU-2021:1313-1

  • python-aiohttp openSUSE Tumbleweed 3.14.3-1.1
  • python-aiohttp openSUSE Tumbleweed 3.8.5-2.1

opensuse advisories openSUSE-SU-2026:11467-1openSUSE-SU-2024:13209-1

  • python-aiohttp Arch Linux 3.7.4-1

arch linux advisories AVG-1623

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-21330 updated cvss 8.2

python-aiohttp: Open redirect in aiohttp.web_middlewares.normalize_path_middleware

  • Red Hat Satellite 6.10 python-aiohttp 3.7.4-1.el7pc Red Hat Satellite Capsule 6.10 python-aiohttp 3.7.4-1.el7pc
    fixed: vendor fix RHSA-2021:4702
  • Red Hat Ansible Automation Platform 1.2 aiohttp, python-aiohttp Red Hat Ansible Tower 3 aiohttp Red Hat Satellite 6.10 tfm 7.0-1.el7sat, gofer 2.12.5-7.el7sat, katello 4.1.1-2.el7sat, libsolv 0.7.20-1.el7pc, receptor 0.6.4-2.el7ar, libcomps 0.1.15-1.el7pc, +584 more Red Hat Satellite Capsule 6.10 tfm 7.0-1.el7sat, katello 4.1.1-2.el7sat, libsolv 0.7.20-1.el7pc, libcomps 0.1.15-1.el7pc, python-rq 1.8.1-1.el7pc, python-idna 2.10-1.el7pc, +368 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.91% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N
GitHub 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
pypi aiohttp
<3.7.4
3.7.4

Affected products

  • aio-libs aiohttp

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.