High
Security advisory
An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An attacker may potentially exploit this issue to bypass a reverse proxy (which also has a poor header check), which may lead to an HTTP Request Smuggling attack.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2020-25613
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 08:57 UTC · Revision 1
Source evidence
An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An attacker may potentially exploit this issue to bypass a reverse proxy (which also has a poor header check), which may lead to an HTTP Request Smuggling attack.
osv:CVE-2020-25613
Complete source record
{
"id": "bd105f819cb5cfac88f2b4e9502afd9b712e16a493fe8338234f8261417e0fe5",
"url": "https://osv.dev/vulnerability/CVE-2020-25613",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2020-25613",
"summary": "An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An attacker may potentially exploit this issue to bypass a reverse proxy (which also has a poor header check), which may lead to an HTTP Request Smuggling attack.",
"evidence": "osv:CVE-2020-25613",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2020-25613",
"aliases": [
"BIT-ruby-2020-25613",
"BIT-ruby-min-2020-25613",
"CVE-2020-25613",
"GHSA-gwfg-cqmg-cf8f"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/ruby/ruby",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"last_affected": "4992d9fd706a9cbe98c4b94e2dbcfc10e317e091"
},
{
"introduced": "c1af7b1e1d408f9796a5f46c9ed36bc5adea4aa2"
},
{
"last_affected": "27958c2bd64b27d529f81a130bd488ccc6b9b1d4"
},
{
"introduced": "647ee6f091eafcce70ffb75ddf7e121e192ab217"
},
{
"last_affected": "a0c7c23c9cec0d0ffcba012279cd652d28ad5bf3"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"last_affected": "2.5.8"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "2.6.0"
},
{
"last_affected": "2.6.6"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "2.7.0"
},
{
"last_affected": "2.7.1"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v2_7_1",
"v2_5_8",
"v2_6_6",
"v2_7_0",
"v1_0_r2"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-25613.json"
}
},
{
"ranges": [
{
"repo": "https://github.com/ruby/webrick",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"last_affected": "c5635fa5e2d4b7d5ca2e08e4c1ae6ec13c7237ec"
},
{
"fixed": "8946bb38b4d87549f0d99ed73c62c41933f97cc7"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:ruby-lang:webrick:*:*:*:*:*:ruby:*:*",
"range": [
{
"introduced": "0"
},
{
"last_affected": "1.6.0"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "8946bb38b4d87549f0d99ed73c62c41933f97cc7"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"v1.6.0",
"v1.5.0",
"v1.4.2",
"v1.4.1",
"v1.4.0",
"v1.4.0.beta1"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-25613.json"
}
}
],
"modified": "2026-10-24T10:51:22.421347064Z",
"provider": "osv",
"references": [
"https://lists.debian.org/debian-lts-announce/2023/04/msg00033.html",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PFP3E7KXXT3H3KA6CBZPUOGA5VPFARRJ/",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YTZURYROG3FFED3TYCQOBV66BS4K6WOV/",
"https://security.gentoo.org/glsa/202401-27",
"https://security.netapp.com/advisory/ntap-20210115-0008/",
"https://www.ruby-lang.org/en/news/2020/09/29/http-request-smuggling-cve-2020-25613/",
"https://hackerone.com/reports/965267",
"https://github.com/ruby/webrick/commit/8946bb38b4d87549f0d99ed73c62c41933f97cc7"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*",
"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*"
],
"vendor_product": "fedoraproject:fedora",
"extracted_events": [
{
"range": [
{
"introduced": "32"
},
{
"last_affected": "32"
},
{
"introduced": "33"
},
{
"last_affected": "33"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2020-25613",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 442565,
"published_at": "2020-10-06T13:15:13.823+00:00"
}