Medium
Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-21330
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 11:32 UTC · Revision 1
Source evidence
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.
osv:CVE-2021-21330
Complete source record
{
"id": "62dbeedb56a395ab0564a10bc0824016cab2db3fbd1f5f28b3a608830cb05beb",
"url": "https://osv.dev/vulnerability/CVE-2021-21330",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-21330",
"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.",
"evidence": "osv:CVE-2021-21330",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2021-21330",
"aliases": [
"CVE-2021-21330",
"GHSA-v6wp-4m6f-gcjg",
"PYSEC-2021-76"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/aio-libs/aiohttp",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "0a26acc1de9e1b0244456b7881ec16ba8bb64fc3"
},
{
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}
],
"database_specific": {
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{
"cpe": "cpe:2.3:a:aiohttp:aiohttp:*:*:*:*:*:*:*:*",
"range": [
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{
"fixed": "3.7.4"
}
],
"source": "CPE_RANGE"
},
{
"range": [
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}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
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"v3.4.0a3",
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"v2.3.0a3",
"v2.3.0a2",
"v2.3.0a1",
"v2.2.0",
"v2.1.0",
"2.0.0",
"2.0.0rc1",
"1.3.0",
"v1.2.0",
"v1.1.1",
"v1.1.0",
"v1.0.1",
"v1.0.0",
"v0.22.1",
"v0.22.0",
"v0.22.0b6",
"v0.22.0b5",
"v0.22.0b4",
"v0.22.0b3",
"v0.22.0b2",
"v0.22.0b1",
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"4v0.21.6",
"v0.21.0",
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"v0.20.0",
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"v0.7.0",
"v.0.6.5",
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"v0.6.3",
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"v0.4.1",
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-21330.json"
}
}
],
"modified": "2026-10-20T10:54:29.054143098Z",
"provider": "osv",
"references": [
"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://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst#374-2021-02-25",
"https://github.com/aio-libs/aiohttp/security/advisories/GHSA-v6wp-4m6f-gcjg",
"https://security.gentoo.org/glsa/202208-19",
"https://www.debian.org/security/2021/dsa-4864",
"https://github.com/aio-libs/aiohttp/commit/2545222a3853e31ace15d87ae0e2effb7da0c96b",
"https://pypi.org/project/aiohttp/"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "10.0"
},
{
"last_affected": "10.0"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
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"cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*"
],
"vendor_product": "fedoraproject:fedora",
"extracted_events": [
{
"range": [
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},
{
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},
{
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},
{
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}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2021-21330",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 385442,
"published_at": "2021-02-26T03:15:12.84+00:00"
}