High
orthanc — security advisory
A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with `Content-Encoding: gzip`. The server does not enforce limits on decompressed size and allocates memory based on attacker-controlled compression metadata. A specially crafted gzip payload can trigger excessive memory allocation and exhaust system memory.
- Products
- orthanc
- Affected versions
- 0.9.4+dfsg-1, 0.9.4+dfsg-2, 0.9.5+dfsg-1, 1.0.0+dfsg-1, 1.0.0+dfsg-1build1, 1.10.0+dfsg-1, 1.12.1+dfsg-3, 1.12.1+dfsg-4, 1.12.1+dfsg-4build1, 1.12.10+dfsg-1, 1.12.10+dfsg-1build1, 1.12.10+dfsg-2, 1.12.11+dfsg-8, 1.12.11+dfsg-8build1, 1.12.2+dfsg-1, 1.12.2+dfsg-1build3, 1.12.2+dfsg-1build4, 1.12.6+dfsg-1, 1.12.7+dfsg-4, 1.12.7+dfsg-4build2, 1.12.9+dfsg-2, 1.3.0+dfsg-1build1, 1.3.0+dfsg-1build2, 1.3.1+dfsg-1, 1.3.1+dfsg-1build1, 1.3.1+dfsg-1build2, 1.5.7+dfsg-2, 1.5.8+dfsg-2, 1.5.8+dfsg-2ubuntu2, 1.5.8+dfsg-2ubuntu3, 1.5.8+dfsg-2ubuntu4, 1.5.8+dfsg-2ubuntu5, 1.5.8+dfsg-2ubuntu6, 1.9.2+really1.9.1+dfsg-1, 1.9.7+dfsg-3ubuntu1, 1.9.7+dfsg-3ubuntu2, 1.9.7+dfsg-4, 1.9.7+dfsg-5, 1.9.7+dfsg-6
- Fixed versions
- Not specified
- CVEs
- CVE-2026-5438
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:28 UTC · Revision 1
Source evidence
A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with `Content-Encoding: gzip`. The server does not enforce limits on decompressed size and allocates memory based on attacker-controlled compression metadata. A specially crafted gzip payload can trigger excessive memory allocation and exhaust system memory.
osv:UBUNTU-CVE-2026-5438
orthanc
Fixed versions: Not specified
orthanc
Fixed versions: Not specified
orthanc
Fixed versions: Not specified
orthanc
Fixed versions: Not specified
orthanc
Fixed versions: Not specified
orthanc
Fixed versions: Not specified
orthanc
Fixed versions: Not specified
orthanc
Fixed versions: Not specified
Complete source record
{
"id": "51d90c6585bce4da1493bc61b8dda7e709dee53cd7803e8f164e7cc54e6c07ef",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-5438",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-5438",
"summary": "A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with `Content-Encoding: gzip`. The server does not enforce limits on decompressed size and allocates memory based on attacker-controlled compression metadata. A specially crafted gzip payload can trigger excessive memory allocation and exhaust system memory.",
"evidence": "osv:UBUNTU-CVE-2026-5438",
"products": [
{
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"evidence": "/affected/0/package/name"
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{
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{
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"evidence": "/affected/0/versions"
},
{
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"evidence": "/affected/0/versions"
},
{
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"evidence": "/affected/0/versions"
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{
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{
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{
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{
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{
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{
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{
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"evidence": "/affected/2/versions"
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{
"name": {
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"affected_versions": [
{
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{
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"evidence": "/affected/3/versions"
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{
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{
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{
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},
{
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{
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{
"name": {
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"prerequisites": [],
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"affected_versions": [
{
"value": "1.12.1+dfsg-3",
"evidence": "/affected/4/versions"
},
{
"value": "1.12.1+dfsg-4",
"evidence": "/affected/4/versions"
},
{
"value": "1.12.1+dfsg-4build1",
"evidence": "/affected/4/versions"
},
{
"value": "1.12.2+dfsg-1",
"evidence": "/affected/4/versions"
},
{
"value": "1.12.2+dfsg-1build3",
"evidence": "/affected/4/versions"
},
{
"value": "1.12.2+dfsg-1build4",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
"value": "orthanc",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.12.6+dfsg-1",
"evidence": "/affected/5/versions"
},
{
"value": "1.12.7+dfsg-4",
"evidence": "/affected/5/versions"
},
{
"value": "1.12.7+dfsg-4build2",
"evidence": "/affected/5/versions"
}
]
},
{
"name": {
"value": "orthanc",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.12.10+dfsg-2",
"evidence": "/affected/6/versions"
},
{
"value": "1.12.11+dfsg-8",
"evidence": "/affected/6/versions"
},
{
"value": "1.12.11+dfsg-8build1",
"evidence": "/affected/6/versions"
}
]
},
{
"name": {
"value": "orthanc",
"evidence": "/affected/7/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.12.7+dfsg-4build2",
"evidence": "/affected/7/versions"
},
{
"value": "1.12.9+dfsg-2",
"evidence": "/affected/7/versions"
},
{
"value": "1.12.10+dfsg-1",
"evidence": "/affected/7/versions"
},
{
"value": "1.12.10+dfsg-1build1",
"evidence": "/affected/7/versions"
},
{
"value": "1.12.10+dfsg-2",
"evidence": "/affected/7/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-5438",
"aliases": [
"UBUNTU-CVE-2026-5438"
],
"metrics": [
{
"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": [
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],
"package": {
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"purl": "pkg:deb/ubuntu/orthanc?arch=source&distro=xenial",
"ecosystem": "Ubuntu:16.04:LTS"
},
"versions": [
"0.9.4+dfsg-1",
"0.9.4+dfsg-2",
"0.9.5+dfsg-1",
"1.0.0+dfsg-1",
"1.0.0+dfsg-1build1"
],
"database_specific": {
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},
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},
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"1.3.0+dfsg-1build1",
"1.3.0+dfsg-1build2",
"1.3.1+dfsg-1",
"1.3.1+dfsg-1build1",
"1.3.1+dfsg-1build2"
],
"database_specific": {
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},
"ecosystem_specific": {
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{
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}
]
}
},
{
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{
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}
],
"package": {
"name": "orthanc",
"purl": "pkg:deb/ubuntu/orthanc?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"1.5.7+dfsg-2",
"1.5.8+dfsg-2",
"1.5.8+dfsg-2ubuntu2",
"1.5.8+dfsg-2ubuntu3",
"1.5.8+dfsg-2ubuntu4",
"1.5.8+dfsg-2ubuntu5",
"1.5.8+dfsg-2ubuntu6"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5438.json"
},
"ecosystem_specific": {
"binaries": [
{
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}
]
}
},
{
"ranges": [
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],
"package": {
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"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
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"1.9.7+dfsg-3ubuntu1",
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"1.9.7+dfsg-5",
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"1.10.0+dfsg-1"
],
"database_specific": {
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},
"ecosystem_specific": {
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{
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},
{
"binary_name": "orthanc",
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}
]
}
},
{
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],
"package": {
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"purl": "pkg:deb/ubuntu/orthanc?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"1.12.1+dfsg-3",
"1.12.1+dfsg-4",
"1.12.1+dfsg-4build1",
"1.12.2+dfsg-1",
"1.12.2+dfsg-1build3",
"1.12.2+dfsg-1build4"
],
"database_specific": {
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},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "liborthancframework1",
"binary_version": "1.12.2+dfsg-1build4"
},
{
"binary_name": "orthanc",
"binary_version": "1.12.2+dfsg-1build4"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
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}
],
"package": {
"name": "orthanc",
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"ecosystem": "Ubuntu:25.10"
},
"versions": [
"1.12.6+dfsg-1",
"1.12.7+dfsg-4",
"1.12.7+dfsg-4build2"
],
"database_specific": {
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},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "liborthancframework1",
"binary_version": "1.12.7+dfsg-4build2"
},
{
"binary_name": "orthanc",
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}
]
}
},
{
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{
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}
]
}
],
"package": {
"name": "orthanc",
"purl": "pkg:deb/ubuntu/orthanc?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"1.12.10+dfsg-2",
"1.12.11+dfsg-8",
"1.12.11+dfsg-8build1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5438.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "liborthancframework1",
"binary_version": "1.12.11+dfsg-8build1"
},
{
"binary_name": "liborthancframework1.12.11",
"binary_version": "1.12.11+dfsg-8build1"
},
{
"binary_name": "orthanc",
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}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
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{
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}
]
}
],
"package": {
"name": "orthanc",
"purl": "pkg:deb/ubuntu/orthanc?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"1.12.7+dfsg-4build2",
"1.12.9+dfsg-2",
"1.12.10+dfsg-1",
"1.12.10+dfsg-1build1",
"1.12.10+dfsg-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5438.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "liborthancframework1",
"binary_version": "1.12.10+dfsg-2"
},
{
"binary_name": "orthanc",
"binary_version": "1.12.10+dfsg-2"
}
]
}
}
],
"modified": "2026-10-17T12:58:35.441601136Z",
"provider": "osv",
"upstream": [
"CVE-2026-5438"
],
"references": [
"https://ubuntu.com/security/CVE-2026-5438",
"https://www.cve.org/CVERecord?id=CVE-2026-5438",
"https://kb.cert.org/vuls/id/536588",
"https://www.machinespirits.de/",
"https://www.orthanc-server.com/"
]
},
"related_cves": [
{
"value": "CVE-2026-5438",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 358820,
"published_at": "2026-04-09T15:16:00+00:00"
}