{"cve":"CVE-2021-21330","nvd":{"published":"2021-02-26T03:15:12.840","modified":"2026-06-17T03:35:18.640","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-601"],"references":["https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst#374-2021-02-25","https://github.com/aio-libs/aiohttp/commit/2545222a3853e31ace15d87ae0e2effb7da0c96b","https://github.com/aio-libs/aiohttp/security/advisories/GHSA-v6wp-4m6f-gcjg","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/"],"products":["aiohttp:aiohttp","debian:debian_linux","fedoraproject:fedora"],"source":"nvd","synced_at":"2026-10-19T21:15:50.279857260+00:00"},"epss":{"cve":"CVE-2021-21330","score":0.01905,"percentile":0.79718,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-v6wp-4m6f-gcjg","url":"https://osv.dev/vulnerability/GHSA-v6wp-4m6f-gcjg","summary":"`aiohttp` Open Redirect vulnerability (`normalize_path_middleware` middleware)","modified":"2026-07-08T06:27:43.955932046Z","packages":[{"ecosystem":"PyPI","name":"aiohttp","purl":"pkg:pypi/aiohttp","ranges":["<3.7.4"],"fixed":["3.7.4"]}]},{"id":"PYSEC-2021-76","url":"https://osv.dev/vulnerability/PYSEC-2021-76","summary":"","modified":"2023-11-08T04:04:41.517445Z","packages":[{"ecosystem":"PyPI","name":"aiohttp","purl":"pkg:pypi/aiohttp","ranges":["<3.7.4"],"fixed":["3.7.4"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}