MediumFix 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::Static#applicable_rules evaluates several header_rules types against the raw URL-encoded PATH_INFO, while the underlying file-serving path is decoded before the file is served. As a result, a request for a URL-encoded variant of a static path can serve the same file without the headers that header_rules were intended to apply. In deployments that rely on Rack::Static to attach security-relevant response headers to static content, this can allow an attacker to bypass those headers by requesting an encoded form of the path. 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~esm11, 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+esm10, 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
- 1.6.4-4ubuntu0.2+esm10, 2.1.4-5ubuntu1.2+esm3, 2.2.7-1ubuntu0.7, 3.1.16-0.1ubuntu0.3
- CVEs
- CVE-2026-34786
- 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::Static#applicable_rules evaluates several header_rules types against the raw URL-encoded PATH_INFO, while the underlying file-serving path is decoded before the file is served. As a result, a request for a URL-encoded variant of a static path can serve the same file without the headers that header_rules were intended to apply. In deployments that rely on Rack::Static to attach security-relevant response headers to static content, this can allow an attacker to bypass those headers by requesting an encoded form of the path. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
osv:UBUNTU-CVE-2026-34786
ruby-rack
Fixed versions: Not specified
ruby-rack
Fixed versions: Not specified
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": "840ff5c3285fd620dd2ec54b0abe58f29909a2ce16e2270e8e5d4421a81fff01",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-34786",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-34786",
"summary": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static#applicable_rules evaluates several header_rules types against the raw URL-encoded PATH_INFO, while the underlying file-serving path is decoded before the file is served. As a result, a request for a URL-encoded variant of a static path can serve the same file without the headers that header_rules were intended to apply. In deployments that rely on Rack::Static to attach security-relevant response headers to static content, this can allow an attacker to bypass those headers by requesting an encoded form of the path. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.",
"evidence": "osv:UBUNTU-CVE-2026-34786",
"products": [
{
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"value": "ruby-rack",
"evidence": "/affected/0/package/name"
},
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"affected_versions": [
{
"value": "1.5.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.5.2-1ubuntu0.1~esm1",
"evidence": "/affected/0/versions"
},
{
"value": "1.5.2-3+deb8u3ubuntu1~esm2",
"evidence": "/affected/0/versions"
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{
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"evidence": "/affected/0/versions"
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{
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"evidence": "/affected/0/versions"
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{
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"evidence": "/affected/0/versions"
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{
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"evidence": "/affected/0/versions"
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{
"value": "1.5.2-3+deb8u3ubuntu1~esm8",
"evidence": "/affected/0/versions"
},
{
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"evidence": "/affected/0/versions"
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{
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{
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{
"name": {
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"affected_versions": [
{
"value": "1.5.2-4",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.4-2",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.4-3",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.4-3ubuntu0.1",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.4-3ubuntu0.2",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.4-3ubuntu0.2+esm1",
"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3ubuntu0.2+esm2",
"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3ubuntu0.2+esm4",
"evidence": "/affected/1/versions"
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{
"value": "1.6.4-3ubuntu0.2+esm5",
"evidence": "/affected/1/versions"
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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"
},
{
"value": "1.6.4-3ubuntu0.2+esm9",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.4-3ubuntu0.2+esm10",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "ruby-rack",
"evidence": "/affected/2/package/name"
},
"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"
},
{
"value": "1.6.4-4ubuntu0.2+esm2",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2+esm4",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2+esm5",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2+esm6",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2+esm7",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2+esm8",
"evidence": "/affected/2/versions"
},
{
"value": "1.6.4-4ubuntu0.2+esm9",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "ruby-rack",
"evidence": "/affected/3/package/name"
},
"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"
},
{
"value": "2.1.4-5ubuntu1.1+esm2",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1.2",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1.2+esm1",
"evidence": "/affected/3/versions"
},
{
"value": "2.1.4-5ubuntu1.2+esm2",
"evidence": "/affected/3/versions"
}
]
},
{
"name": {
"value": "ruby-rack",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.2.7-1ubuntu0.7",
"evidence": "/affected/4/ranges"
}
],
"affected_versions": [
{
"value": "2.2.4-3",
"evidence": "/affected/4/versions"
},
{
"value": "2.2.7-1",
"evidence": "/affected/4/versions"
},
{
"value": "2.2.7-1ubuntu0.1",
"evidence": "/affected/4/versions"
},
{
"value": "2.2.7-1ubuntu0.2",
"evidence": "/affected/4/versions"
},
{
"value": "2.2.7-1ubuntu0.3",
"evidence": "/affected/4/versions"
},
{
"value": "2.2.7-1ubuntu0.4",
"evidence": "/affected/4/versions"
},
{
"value": "2.2.7-1ubuntu0.5",
"evidence": "/affected/4/versions"
},
{
"value": "2.2.7-1ubuntu0.6",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
"value": "ruby-rack",
"evidence": "/affected/5/package/name"
},
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"fixed_versions": [
{
"value": "3.1.16-0.1ubuntu0.3",
"evidence": "/affected/5/ranges"
}
],
"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": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-34786",
"aliases": [
"UBUNTU-CVE-2026-34786"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
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}
]
}
],
"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",
"1.5.2-3+deb8u3ubuntu1~esm11"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34786.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "librack-ruby",
"binary_version": "1.5.2-3+deb8u3ubuntu1~esm11"
},
{
"binary_name": "librack-ruby1.8",
"binary_version": "1.5.2-3+deb8u3ubuntu1~esm11"
},
{
"binary_name": "librack-ruby1.9.1",
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},
{
"binary_name": "ruby-rack",
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}
]
}
},
{
"ranges": [
{
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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",
"1.6.4-3ubuntu0.2+esm10"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34786.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "ruby-rack",
"binary_version": "1.6.4-3ubuntu0.2+esm10"
}
]
}
},
{
"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-2026-34786.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-2026-34786.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-2026-34786.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-2026-34786.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-2026-34786.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "ruby-rack",
"binary_version": "3.2.4-1ubuntu1"
}
]
}
}
],
"modified": "2026-10-25T23:30:02.995570932Z",
"provider": "osv",
"upstream": [
"CVE-2026-34786"
],
"references": [
"https://ubuntu.com/security/CVE-2026-34786",
"https://www.cve.org/CVERecord?id=CVE-2026-34786",
"https://github.com/rack/rack/security/advisories/GHSA-q4qf-9j86-f5mh",
"https://ubuntu.com/security/notices/USN-8182-1"
]
},
"related_cves": [
{
"value": "CVE-2026-34786",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 446232,
"published_at": "2026-04-02T17:16:00+00:00"
}