Medium
Security advisory
An issue was discovered in Symfony 4.2.0 to 4.2.11 and 4.3.0 to 4.3.7. The ability to enumerate users was possible due to different handling depending on whether the user existed when making unauthorized attempts to use the switch users functionality. This is related to symfony/security.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2019-18886
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 08:36 UTC · Revision 1
Source evidence
An issue was discovered in Symfony 4.2.0 to 4.2.11 and 4.3.0 to 4.3.7. The ability to enumerate users was possible due to different handling depending on whether the user existed when making unauthorized attempts to use the switch users functionality. This is related to symfony/security.
osv:CVE-2019-18886
Complete source record
{
"id": "705fddb3cf34c7b9931f6a0b407a584403524b907110b994d2038bbcc11640d8",
"url": "https://osv.dev/vulnerability/CVE-2019-18886",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2019-18886",
"summary": "An issue was discovered in Symfony 4.2.0 to 4.2.11 and 4.3.0 to 4.3.7. The ability to enumerate users was possible due to different handling depending on whether the user existed when making unauthorized attempts to use the switch users functionality. This is related to symfony/security.",
"evidence": "osv:CVE-2019-18886",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2019-18886",
"aliases": [
"CVE-2019-18886",
"GHSA-4vpc-5jx4-cfqg"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/symfony/security-http",
"type": "GIT",
"events": [
{
"introduced": "34e089af7d363bd2ded8ad15f06b2b97348b97e5"
},
{
"last_affected": "a3eddd912d93a8c77ffee2b31448e13864257f4e"
},
{
"introduced": "13594beb3faaeea891aaae9eeea8ffde16a99faf"
},
{
"last_affected": "a2f67dfe0ecfb713734847f4ada0f4231e28ae71"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "4.2.0"
},
{
"last_affected": "4.2.11"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "4.3.0"
},
{
"last_affected": "4.3.7"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v4.2.11",
"v4.2.10",
"v4.2.9",
"v4.2.8",
"v4.2.7",
"v4.2.6",
"v4.2.5",
"v4.2.4",
"v4.2.3",
"v4.2.2",
"v4.2.1",
"v4.2.0-RC1",
"v4.2.0-BETA2",
"v4.2.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-18886.json"
}
},
{
"ranges": [
{
"repo": "https://github.com/symfony/symfony",
"type": "GIT",
"events": [
{
"introduced": "7bd9a1bae87e6b2d7eba499ebf3053ff4bc3a483"
},
{
"last_affected": "2ba6f17744ee8649ac107039f64d1ee4c959bf32"
},
{
"introduced": "0bf8d128ef3c492436ab5f1b7c7b130f9e96aad2"
},
{
"last_affected": "fb4065ac95f08ca26ee605936e537ba2cd4a6bb7"
},
{
"fixed": "87fb08703e62882a7a6fdb17672070e0ee12dd65"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "4.2.0"
},
{
"last_affected": "4.2.11"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "4.3.0"
},
{
"last_affected": "4.3.7"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "87fb08703e62882a7a6fdb17672070e0ee12dd65"
}
],
"source": "REFERENCES_TAG",
"original_tag": "v4.3.8"
}
]
}
}
],
"versions": [
"v4.3.7",
"v4.3.6",
"v4.3.5",
"v4.3.4",
"v4.3.3",
"v4.2.11",
"v4.3.2",
"v4.2.10",
"v4.3.1",
"v4.3.0",
"v4.2.9",
"v4.2.8",
"v4.2.7",
"v4.2.6",
"v4.2.5",
"v4.2.4",
"v4.2.3",
"v4.2.2",
"v4.2.1",
"v4.2.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-18886.json"
}
}
],
"modified": "2026-10-24T10:47:42.352103533Z",
"provider": "osv",
"references": [
"https://github.com/symfony/symfony/releases/tag/v4.3.8",
"https://symfony.com/blog/cve-2019-18886-prevent-user-enumeration-using-switch-user-functionality",
"https://symfony.com/blog/symfony-4-3-8-released"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2019-18886",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 441485,
"published_at": "2019-11-21T18:15:11.82+00:00"
}