HighFix available
ruby-rack — security advisory
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.select_best_encoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard (*) entries. Because this method is used by Rack::Deflater to choose a response encoding, an unauthenticated attacker can send a single request with a crafted Accept-Encoding header and cause disproportionate CPU consumption on the compression middleware path. This results in a denial of service condition for applications using Rack::Deflater. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
- Products
- ruby-rack
- Affected versions
- 1.5.2-1, 1.5.2-1ubuntu0.1~esm1, 1.5.2-3+deb8u3ubuntu1~esm10, 1.5.2-3+deb8u3ubuntu1~esm2, 1.5.2-3+deb8u3ubuntu1~esm3, 1.5.2-3+deb8u3ubuntu1~esm4, 1.5.2-3+deb8u3ubuntu1~esm6, 1.5.2-3+deb8u3ubuntu1~esm7, 1.5.2-3+deb8u3ubuntu1~esm8, 1.5.2-3+deb8u3ubuntu1~esm9, 1.5.2-4, 1.6.4-2, 1.6.4-3, 1.6.4-3ubuntu0.1, 1.6.4-3ubuntu0.2, 1.6.4-3ubuntu0.2+esm1, 1.6.4-3ubuntu0.2+esm2, 1.6.4-3ubuntu0.2+esm4, 1.6.4-3ubuntu0.2+esm5, 1.6.4-3ubuntu0.2+esm6, 1.6.4-3ubuntu0.2+esm7, 1.6.4-3ubuntu0.2+esm8, 1.6.4-3ubuntu0.2+esm9, 1.6.4-4, 1.6.4-4ubuntu0.1, 1.6.4-4ubuntu0.2, 1.6.4-4ubuntu0.2+esm1, 1.6.4-4ubuntu0.2+esm2, 1.6.4-4ubuntu0.2+esm4, 1.6.4-4ubuntu0.2+esm5, 1.6.4-4ubuntu0.2+esm6, 1.6.4-4ubuntu0.2+esm7, 1.6.4-4ubuntu0.2+esm8, 1.6.4-4ubuntu0.2+esm9, 2.1.4-3, 2.1.4-4, 2.1.4-5, 2.1.4-5ubuntu1, 2.1.4-5ubuntu1+esm2, 2.1.4-5ubuntu1+esm3, 2.1.4-5ubuntu1+esm4, 2.1.4-5ubuntu1+esm5, 2.1.4-5ubuntu1.1, 2.1.4-5ubuntu1.1+esm1, 2.1.4-5ubuntu1.1+esm2, 2.1.4-5ubuntu1.2, 2.1.4-5ubuntu1.2+esm1, 2.1.4-5ubuntu1.2+esm2, 2.2.4-3, 2.2.7-1, 2.2.7-1.1, 2.2.7-1ubuntu0.1, 2.2.7-1ubuntu0.2, 2.2.7-1ubuntu0.3, 2.2.7-1ubuntu0.4, 2.2.7-1ubuntu0.5, 2.2.7-1ubuntu0.6, 3.1.16-0.1, 3.1.16-0.1ubuntu0.1, 3.1.16-0.1ubuntu0.2, 3.1.18-1, 3.1.18-1build1, 3.2.4-1ubuntu1
- Fixed versions
- 1.5.2-3+deb8u3ubuntu1~esm11, 1.6.4-3ubuntu0.2+esm10, 1.6.4-4ubuntu0.2+esm10, 2.1.4-5ubuntu1.2+esm3, 2.2.7-1ubuntu0.7, 3.1.16-0.1ubuntu0.3
- CVEs
- CVE-2026-34230
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 10:26 UTC · Revision 1
Source evidence
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.select_best_encoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard (*) entries. Because this method is used by Rack::Deflater to choose a response encoding, an unauthenticated attacker can send a single request with a crafted Accept-Encoding header and cause disproportionate CPU consumption on the compression middleware path. This results in a denial of service condition for applications using Rack::Deflater. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
osv:UBUNTU-CVE-2026-34230
ruby-rack
Fixed versions: 1.5.2-3+deb8u3ubuntu1~esm11
ruby-rack
Fixed versions: 1.6.4-3ubuntu0.2+esm10
ruby-rack
Fixed versions: 1.6.4-4ubuntu0.2+esm10
ruby-rack
Fixed versions: 2.1.4-5ubuntu1.2+esm3
ruby-rack
Fixed versions: 2.2.7-1ubuntu0.7
ruby-rack
Fixed versions: 3.1.16-0.1ubuntu0.3
ruby-rack
Fixed versions: Not specified
Complete source record
{
"id": "46ae42b87c44880af39c43c06c7f1189842493432fc7f8338685d1d9d6844404",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-34230",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-34230",
"summary": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.select_best_encoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard (*) entries. Because this method is used by Rack::Deflater to choose a response encoding, an unauthenticated attacker can send a single request with a crafted Accept-Encoding header and cause disproportionate CPU consumption on the compression middleware path. This results in a denial of service condition for applications using Rack::Deflater. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.",
"evidence": "osv:UBUNTU-CVE-2026-34230",
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{
"value": "1.5.2-1",
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{
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{
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{
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{
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"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3",
"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3ubuntu0.1",
"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3ubuntu0.2",
"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3ubuntu0.2+esm1",
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{
"value": "1.6.4-3ubuntu0.2+esm2",
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{
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{
"value": "1.6.4-3ubuntu0.2+esm5",
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{
"value": "1.6.4-3ubuntu0.2+esm6",
"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3ubuntu0.2+esm7",
"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3ubuntu0.2+esm8",
"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3ubuntu0.2+esm9",
"evidence": "/affected/1/versions"
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]
},
{
"name": {
"value": "ruby-rack",
"evidence": "/affected/2/package/name"
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"prerequisites": [],
"fixed_versions": [
{
"value": "1.6.4-4ubuntu0.2+esm10",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "1.6.4-4",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.1",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2+esm1",
"evidence": "/affected/2/versions"
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{
"value": "1.6.4-4ubuntu0.2+esm2",
"evidence": "/affected/2/versions"
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{
"value": "1.6.4-4ubuntu0.2+esm4",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2+esm5",
"evidence": "/affected/2/versions"
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{
"value": "1.6.4-4ubuntu0.2+esm6",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2+esm7",
"evidence": "/affected/2/versions"
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{
"value": "1.6.4-4ubuntu0.2+esm8",
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{
"value": "1.6.4-4ubuntu0.2+esm9",
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{
"name": {
"value": "ruby-rack",
"evidence": "/affected/3/package/name"
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"prerequisites": [],
"fixed_versions": [
{
"value": "2.1.4-5ubuntu1.2+esm3",
"evidence": "/affected/3/ranges"
}
],
"affected_versions": [
{
"value": "2.1.4-3",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-4",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1+esm2",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1+esm3",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1+esm4",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1+esm5",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1.1",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1.1+esm1",
"evidence": "/affected/3/versions"
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{
"value": "2.1.4-5ubuntu1.1+esm2",
"evidence": "/affected/3/versions"
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{
"value": "2.1.4-5ubuntu1.2",
"evidence": "/affected/3/versions"
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{
"value": "2.1.4-5ubuntu1.2+esm1",
"evidence": "/affected/3/versions"
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{
"value": "2.1.4-5ubuntu1.2+esm2",
"evidence": "/affected/3/versions"
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]
},
{
"name": {
"value": "ruby-rack",
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},
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{
"value": "2.2.7-1ubuntu0.7",
"evidence": "/affected/4/ranges"
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],
"affected_versions": [
{
"value": "2.2.4-3",
"evidence": "/affected/4/versions"
},
{
"value": "2.2.7-1",
"evidence": "/affected/4/versions"
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{
"value": "2.2.7-1ubuntu0.1",
"evidence": "/affected/4/versions"
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{
"value": "2.2.7-1ubuntu0.2",
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{
"value": "2.2.7-1ubuntu0.3",
"evidence": "/affected/4/versions"
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{
"value": "2.2.7-1ubuntu0.4",
"evidence": "/affected/4/versions"
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{
"value": "2.2.7-1ubuntu0.5",
"evidence": "/affected/4/versions"
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{
"value": "2.2.7-1ubuntu0.6",
"evidence": "/affected/4/versions"
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]
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"name": {
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{
"value": "3.1.16-0.1ubuntu0.3",
"evidence": "/affected/5/ranges"
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],
"affected_versions": [
{
"value": "2.2.7-1.1",
"evidence": "/affected/5/versions"
},
{
"value": "3.1.16-0.1",
"evidence": "/affected/5/versions"
},
{
"value": "3.1.16-0.1ubuntu0.1",
"evidence": "/affected/5/versions"
},
{
"value": "3.1.16-0.1ubuntu0.2",
"evidence": "/affected/5/versions"
}
]
},
{
"name": {
"value": "ruby-rack",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.1.16-0.1",
"evidence": "/affected/6/versions"
},
{
"value": "3.1.18-1",
"evidence": "/affected/6/versions"
},
{
"value": "3.1.18-1build1",
"evidence": "/affected/6/versions"
},
{
"value": "3.2.4-1ubuntu1",
"evidence": "/affected/6/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-34230",
"aliases": [
"UBUNTU-CVE-2026-34230"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.5.2-3+deb8u3ubuntu1~esm11"
}
]
}
],
"package": {
"name": "ruby-rack",
"purl": "pkg:deb/ubuntu/ruby-rack?arch=source&distro=esm-infra-legacy%2Ftrusty",
"ecosystem": "Ubuntu:Pro:14.04:LTS"
},
"versions": [
"1.5.2-1",
"1.5.2-1ubuntu0.1~esm1",
"1.5.2-3+deb8u3ubuntu1~esm2",
"1.5.2-3+deb8u3ubuntu1~esm3",
"1.5.2-3+deb8u3ubuntu1~esm4",
"1.5.2-3+deb8u3ubuntu1~esm6",
"1.5.2-3+deb8u3ubuntu1~esm7",
"1.5.2-3+deb8u3ubuntu1~esm8",
"1.5.2-3+deb8u3ubuntu1~esm9",
"1.5.2-3+deb8u3ubuntu1~esm10"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34230.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "librack-ruby",
"binary_version": "1.5.2-3+deb8u3ubuntu1~esm11"
},
{
"binary_name": "librack-ruby1.8",
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},
{
"binary_name": "librack-ruby1.9.1",
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},
{
"binary_name": "ruby-rack",
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}
],
"availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
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{
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{
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}
]
}
],
"package": {
"name": "ruby-rack",
"purl": "pkg:deb/ubuntu/ruby-rack?arch=source&distro=esm-apps%2Fxenial",
"ecosystem": "Ubuntu:Pro:16.04:LTS"
},
"versions": [
"1.5.2-4",
"1.6.4-2",
"1.6.4-3",
"1.6.4-3ubuntu0.1",
"1.6.4-3ubuntu0.2",
"1.6.4-3ubuntu0.2+esm1",
"1.6.4-3ubuntu0.2+esm2",
"1.6.4-3ubuntu0.2+esm4",
"1.6.4-3ubuntu0.2+esm5",
"1.6.4-3ubuntu0.2+esm6",
"1.6.4-3ubuntu0.2+esm7",
"1.6.4-3ubuntu0.2+esm8",
"1.6.4-3ubuntu0.2+esm9"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34230.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "ruby-rack",
"binary_version": "1.6.4-3ubuntu0.2+esm10"
}
],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.6.4-4ubuntu0.2+esm10"
}
]
}
],
"package": {
"name": "ruby-rack",
"purl": "pkg:deb/ubuntu/ruby-rack?arch=source&distro=esm-apps%2Fbionic",
"ecosystem": "Ubuntu:Pro:18.04:LTS"
},
"versions": [
"1.6.4-4",
"1.6.4-4ubuntu0.1",
"1.6.4-4ubuntu0.2",
"1.6.4-4ubuntu0.2+esm1",
"1.6.4-4ubuntu0.2+esm2",
"1.6.4-4ubuntu0.2+esm4",
"1.6.4-4ubuntu0.2+esm5",
"1.6.4-4ubuntu0.2+esm6",
"1.6.4-4ubuntu0.2+esm7",
"1.6.4-4ubuntu0.2+esm8",
"1.6.4-4ubuntu0.2+esm9"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34230.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "ruby-rack",
"binary_version": "1.6.4-4ubuntu0.2+esm10"
}
],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.1.4-5ubuntu1.2+esm3"
}
]
}
],
"package": {
"name": "ruby-rack",
"purl": "pkg:deb/ubuntu/ruby-rack?arch=source&distro=esm-apps%2Fjammy",
"ecosystem": "Ubuntu:Pro:22.04:LTS"
},
"versions": [
"2.1.4-3",
"2.1.4-4",
"2.1.4-5",
"2.1.4-5ubuntu1",
"2.1.4-5ubuntu1+esm2",
"2.1.4-5ubuntu1+esm3",
"2.1.4-5ubuntu1+esm4",
"2.1.4-5ubuntu1+esm5",
"2.1.4-5ubuntu1.1",
"2.1.4-5ubuntu1.1+esm1",
"2.1.4-5ubuntu1.1+esm2",
"2.1.4-5ubuntu1.2",
"2.1.4-5ubuntu1.2+esm1",
"2.1.4-5ubuntu1.2+esm2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34230.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "ruby-rack",
"binary_version": "2.1.4-5ubuntu1.2+esm3"
}
],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.2.7-1ubuntu0.7"
}
]
}
],
"package": {
"name": "ruby-rack",
"purl": "pkg:deb/ubuntu/ruby-rack?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"2.2.4-3",
"2.2.7-1",
"2.2.7-1ubuntu0.1",
"2.2.7-1ubuntu0.2",
"2.2.7-1ubuntu0.3",
"2.2.7-1ubuntu0.4",
"2.2.7-1ubuntu0.5",
"2.2.7-1ubuntu0.6"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34230.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "ruby-rack",
"binary_version": "2.2.7-1ubuntu0.7"
}
],
"availability": "No subscription required"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.1.16-0.1ubuntu0.3"
}
]
}
],
"package": {
"name": "ruby-rack",
"purl": "pkg:deb/ubuntu/ruby-rack?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
"2.2.7-1.1",
"3.1.16-0.1",
"3.1.16-0.1ubuntu0.1",
"3.1.16-0.1ubuntu0.2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34230.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "ruby-rack",
"binary_version": "3.1.16-0.1ubuntu0.3"
}
],
"availability": "No subscription required"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "ruby-rack",
"purl": "pkg:deb/ubuntu/ruby-rack?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"3.1.16-0.1",
"3.1.18-1",
"3.1.18-1build1",
"3.2.4-1ubuntu1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34230.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "ruby-rack",
"binary_version": "3.2.4-1ubuntu1"
}
]
}
}
],
"modified": "2026-10-25T23:30:04.171231088Z",
"provider": "osv",
"upstream": [
"CVE-2026-34230"
],
"references": [
"https://ubuntu.com/security/CVE-2026-34230",
"https://www.cve.org/CVERecord?id=CVE-2026-34230",
"https://github.com/rack/rack/security/advisories/GHSA-v569-hp3g-36wr",
"https://ubuntu.com/security/notices/USN-8182-1"
]
},
"related_cves": [
{
"value": "CVE-2026-34230",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 446243,
"published_at": "2026-04-02T17:16:00+00:00"
}