Medium
Security advisory
An issue was discovered in Squid 4.x before 4.15 and 5.x before 5.0.6. If a remote server sends a certain response header over HTTP or HTTPS, there is a denial of service. This header can plausibly occur in benign network traffic.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-28662
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 09:29 UTC · Revision 1
Source evidence
An issue was discovered in Squid 4.x before 4.15 and 5.x before 5.0.6. If a remote server sends a certain response header over HTTP or HTTPS, there is a denial of service. This header can plausibly occur in benign network traffic.
osv:CVE-2021-28662
Complete source record
{
"id": "7564b667b86a8ca15e75988900c3d55603f4012cc516d7ba59bb9f05194f74e4",
"url": "https://osv.dev/vulnerability/CVE-2021-28662",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-28662",
"summary": "An issue was discovered in Squid 4.x before 4.15 and 5.x before 5.0.6. If a remote server sends a certain response header over HTTP or HTTPS, there is a denial of service. This header can plausibly occur in benign network traffic.",
"evidence": "osv:CVE-2021-28662",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2021-28662",
"aliases": [
"CVE-2021-28662",
"GHSA-jjq6-mh2h-g39h"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/squid-cache/squid",
"type": "GIT",
"events": [
{
"introduced": "1243ec712bf76c549ba7f48fcdc30d98ce550449"
},
{
"fixed": "648729b05673c6166c5d91c6ee4cda30cc164839"
},
{
"introduced": "0"
},
{
"fixed": "1521895e24671463bf590cabcdbd2acf637ed2c1"
},
{
"fixed": "051824924c709bd6162a378f746fb859454c674e"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "4.0.1"
},
{
"fixed": "4.15"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "5.0"
},
{
"fixed": "5.0.6"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "051824924c709bd6162a378f746fb859454c674e"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"SQUID_4_14",
"SQUID_5_0_5",
"SQUID_4_13",
"SQUID_5_0_4",
"SQUID_4_12",
"SQUID_5_0_3",
"SQUID_5_0_2",
"SQUID_4_11",
"SQUID_5_0_1",
"SQUID_4_10",
"SQUID_4_9",
"SQUID_4_8",
"SQUID_4_7",
"M-staged-PR365",
"M-staged-PR370",
"M-staged-PR376",
"M-staged-PR375",
"SQUID_4_6",
"M-staged-PR373",
"M-staged-PR372",
"M-staged-PR319",
"M-staged-PR366",
"M-staged-PR351",
"M-staged-PR342",
"M-staged-PR364",
"M-staged-PR359",
"SQUID_4_5",
"M-staged-PR348",
"M-staged-PR345",
"SQUID_4_4",
"M-staged-PR314",
"M-staged-PR306",
"SQUID_4_3",
"M-staged-PR294",
"M-staged-PR299",
"M-staged-PR295",
"M-staged-PR293",
"M-staged-PR164",
"SQUID_4_2",
"M-staged-PR276",
"M-staged-PR274",
"SQUID_3_5_27",
"M-staged-PR264",
"M-staged-PR268",
"M-staged-PR267",
"M-staged-PR266",
"M-staged-PR258",
"M-staged-PR230",
"M-staged-PR255",
"M-staged-PR252",
"M-staged-PR229",
"M-staged-PR241",
"M-staged-PR239",
"M-staged-PR242",
"SQUID_4_1",
"M-staged-PR235",
"M-staged-PR238",
"M-staged-PR218",
"M-staged-PR237",
"M-staged-PR227",
"M-staged-PR202",
"M-staged-PR225",
"SQUID_4_0_25",
"M-staged-PR220",
"M-staged-PR221",
"M-staged-PR210",
"M-staged-PR209",
"M-staged-PR208",
"M-staged-PR198",
"M-staged-PR206",
"M-staged-PR182",
"M-staged-PR195",
"M-staged-PR199",
"M-staged-PR200",
"M-staged-PR196",
"M-staged-PR193",
"M-staged-PR181",
"M-staged-PR189",
"M-staged-PR176",
"M-staged-PR186",
"SQUID_4_0_24",
"M-staged-PR179",
"M-staged-PR170",
"M-staged-PR161",
"SQUID_4_0_23",
"SQUID_4_0_22",
"SQUID_4_0_21",
"SQUID_4_0_20",
"SQUID_4_0_19",
"SQUID_4_0_18",
"SQUID_4_0_17",
"SQUID_4_0_16",
"SQUID_4_0_15",
"SQUID_4_0_14",
"SQUID_4_0_13",
"SQUID_4_0_12",
"SQUID_4_0_11",
"SQUID_4_0_10",
"SQUID_4_0_9",
"SQUID_4_0_8",
"SQUID_4_0_7",
"SQUID_4_0_6",
"SQUID_4_0_5",
"SQUID_4_0_4",
"SQUID_4_0_3",
"SQUID_4_0_2",
"SQUID_4_0_1"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-28662.json",
"vanir_signatures": [
{
"id": "CVE-2021-28662-ac67f9e9",
"digest": {
"threshold": 0.9,
"line_hashes": [
"246787021619791419152269128153398552627",
"137540088876487517479355767659710642705",
"2037448173086037427154046699180625686",
"111963318781500401476263553951823657637"
]
},
"source": "https://github.com/squid-cache/squid/commit/051824924c709bd6162a378f746fb859454c674e",
"target": {
"file": "src/http/RegisteredHeaders.cc"
},
"deprecated": false,
"signature_type": "Line",
"signature_version": "v1"
},
{
"id": "CVE-2021-28662-b5ea6bf5",
"digest": {
"length": 211,
"function_hash": "213594514490356346423760141520931754203"
},
"source": "https://github.com/squid-cache/squid/commit/051824924c709bd6162a378f746fb859454c674e",
"target": {
"file": "src/http/RegisteredHeaders.cc",
"function": "HeaderLookupTable_t::lookup"
},
"deprecated": false,
"signature_type": "Function",
"signature_version": "v1"
}
],
"vanir_signatures_modified": "2026-10-24T14:51:06Z"
}
}
],
"modified": "2026-10-24T14:51:06.443727401Z",
"provider": "osv",
"references": [
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/",
"https://www.debian.org/security/2021/dsa-4924",
"https://github.com/squid-cache/squid/commit/051824924c709bd6162a378f746fb859454c674e",
"https://github.com/squid-cache/squid/security/advisories/GHSA-jjq6-mh2h-g39h"
],
"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": [
"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",
"cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*"
],
"vendor_product": "fedoraproject:fedora",
"extracted_events": [
{
"range": [
{
"introduced": "33"
},
{
"last_affected": "33"
},
{
"introduced": "34"
},
{
"last_affected": "34"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2021-28662",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 443862,
"published_at": "2021-05-27T12:15:08.263+00:00"
}