{"id":"CVE-2021-21330","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-21330","generatedAt":"2026-10-27T20:22:45.148Z","title":"In aiohttp before version 3.7.4 there is an open redirect vulnerability.","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.","published":"2021-02-26T03:15:13.000Z","lastModified":"2026-06-17T03:35:19.000Z","status":"Modified","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"cwe":["CWE-601"],"affected":["aiohttp/aiohttp","debian/debian linux","fedoraproject/fedora"],"epss":{"score":0.01905,"percentile":0.79573,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (1.91%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst#374-2021-02-25","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/aio-libs/aiohttp/commit/2545222a3853e31ace15d87ae0e2effb7da0c96b","tags":["Patch","Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/aio-libs/aiohttp/security/advisories/GHSA-v6wp-4m6f-gcjg","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FU7ENI54JNEK3PHEFGCE46DGMFNTVU6L/","source":"security-advisories@github.com"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JN3V7CZJRT4QFCVXB6LDPCJH7NAOFCA5/","source":"security-advisories@github.com"},{"url":"https://pypi.org/project/aiohttp/","tags":["Product","Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://security.gentoo.org/glsa/202208-19","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://www.debian.org/security/2021/dsa-4864","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst#374-2021-02-25","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/aio-libs/aiohttp/commit/2545222a3853e31ace15d87ae0e2effb7da0c96b","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/aio-libs/aiohttp/security/advisories/GHSA-v6wp-4m6f-gcjg","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FU7ENI54JNEK3PHEFGCE46DGMFNTVU6L/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JN3V7CZJRT4QFCVXB6LDPCJH7NAOFCA5/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://pypi.org/project/aiohttp/","tags":["Product","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202208-19","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2021/dsa-4864","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-21330","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}