MediumFix available
squid — security advisory
Squid before 4.15 and 5.x before 5.0.6 allows remote servers to cause a denial of service (affecting availability to all clients) via an HTTP response. The issue trigger is a header that can be expected to exist in HTTP traffic without any malicious intent by the server.
- Products
- squid
- Affected versions
- Not specified
- Fixed versions
- 5.0.6-r0
- CVEs
- CVE-2021-33620
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 22:05 UTC · Revision 1
Source evidence
Squid before 4.15 and 5.x before 5.0.6 allows remote servers to cause a denial of service (affecting availability to all clients) via an HTTP response. The issue trigger is a header that can be expected to exist in HTTP traffic without any malicious intent by the server.
osv:ALPINE-CVE-2021-33620
squid
Fixed versions: 5.0.6-r0
squid
Fixed versions: 5.0.6-r0
squid
Fixed versions: 5.0.6-r0
squid
Fixed versions: 5.0.6-r0
squid
Fixed versions: 5.0.6-r0
squid
Fixed versions: 5.0.6-r0
squid
Fixed versions: 5.0.6-r0
squid
Fixed versions: 5.0.6-r0
squid
Fixed versions: 5.0.6-r0
squid
Fixed versions: 5.0.6-r0
Complete source record
{
"id": "b3260a8eadde0327d6c53e8374a27dd617efcff77208c67e8a3fdb172790c676",
"url": "https://osv.dev/vulnerability/ALPINE-CVE-2021-33620",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "ALPINE-CVE-2021-33620",
"summary": "Squid before 4.15 and 5.x before 5.0.6 allows remote servers to cause a denial of service (affecting availability to all clients) via an HTTP response. The issue trigger is a header that can be expected to exist in HTTP traffic without any malicious intent by the server.",
"evidence": "osv:ALPINE-CVE-2021-33620",
"products": [
{
"name": {
"value": "squid",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "squid",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "squid",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "squid",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/3/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "squid",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/4/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "squid",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/5/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "squid",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/6/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "squid",
"evidence": "/affected/7/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/7/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "squid",
"evidence": "/affected/8/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/8/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "squid",
"evidence": "/affected/9/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.0.6-r0",
"evidence": "/affected/9/ranges"
}
],
"affected_versions": []
}
],
"severity": "medium",
"structured": {
"id": "ALPINE-CVE-2021-33620",
"aliases": [
"ALPINE-CVE-2021-33620"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.0"
},
{
"fixed": "5.0.6-r0"
}
]
}
],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.15"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.0"
},
{
"fixed": "5.0.6-r0"
}
]
}
],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.16"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.0"
},
{
"fixed": "5.0.6-r0"
}
]
}
],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.17"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
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"events": [
{
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{
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}
]
}
],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.18"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.0"
},
{
"fixed": "5.0.6-r0"
}
]
}
],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.19"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
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{
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}
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],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.20"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.0"
},
{
"fixed": "5.0.6-r0"
}
]
}
],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.21"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.0"
},
{
"fixed": "5.0.6-r0"
}
]
}
],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.22"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.0"
},
{
"fixed": "5.0.6-r0"
}
]
}
],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.23"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.0"
},
{
"fixed": "5.0.6-r0"
}
]
}
],
"package": {
"name": "squid",
"purl": "pkg:apk/alpine/squid?arch=source",
"ecosystem": "Alpine:v3.24"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-33620.json"
},
"ecosystem_specific": {}
}
],
"modified": "2026-10-23T17:17:56.190634930Z",
"provider": "osv",
"upstream": [
"CVE-2021-33620"
],
"references": [
"https://security.alpinelinux.org/vuln/CVE-2021-33620"
]
},
"related_cves": [
{
"value": "CVE-2021-33620",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 415458,
"published_at": "2021-05-28T12:15:07.697+00:00"
}