High
btrbk — security advisory
btrbk is a tool for creating snapshots and remote backups of Btrfs subvolumes. From 0.29.0 until 0.32.7, btrbk's ssh_filter_btrbk.sh constructs allow_stream_match with a start anchor but without an end-of-string anchor for the complete command. A user restricted through an authorized_keys forced command can append a trailing pipe command after a valid btrbk command prefix, bypassing the allowlist and executing arbitrary commands with the privileges of the backup-target SSH account. Deployments that do not use ssh_filter_btrbk.sh in authorized_keys are not affected. This issue is fixed in version 0.32.7.
- Products
- btrbk
- Affected versions
- 0.19.3-1, 0.20.0-1, 0.21.0-1, 0.22.0-1, 0.22.1-1, 0.22.2-1, 0.25.1-1, 0.26.0-1, 0.27.1-1, 0.27.1-2, 0.31.3-1, 0.32.5-1, 0.32.6-2
- Fixed versions
- Not specified
- CVEs
- CVE-2026-62943
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:11 UTC · Revision 1
Source evidence
btrbk is a tool for creating snapshots and remote backups of Btrfs subvolumes. From 0.29.0 until 0.32.7, btrbk's ssh_filter_btrbk.sh constructs allow_stream_match with a start anchor but without an end-of-string anchor for the complete command. A user restricted through an authorized_keys forced command can append a trailing pipe command after a valid btrbk command prefix, bypassing the allowlist and executing arbitrary commands with the privileges of the backup-target SSH account. Deployments that do not use ssh_filter_btrbk.sh in authorized_keys are not affected. This issue is fixed in version 0.32.7.
osv:UBUNTU-CVE-2026-62943
btrbk
Fixed versions: Not specified
btrbk
Fixed versions: Not specified
btrbk
Fixed versions: Not specified
btrbk
Fixed versions: Not specified
btrbk
Fixed versions: Not specified
btrbk
Fixed versions: Not specified
btrbk
Fixed versions: Not specified
Complete source record
{
"id": "08113d505611267f477e5838e5ad8d68059cec67aba3b92dfeff1da928ab7041",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-62943",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-62943",
"summary": "btrbk is a tool for creating snapshots and remote backups of Btrfs subvolumes. From 0.29.0 until 0.32.7, btrbk's ssh_filter_btrbk.sh constructs allow_stream_match with a start anchor but without an end-of-string anchor for the complete command. A user restricted through an authorized_keys forced command can append a trailing pipe command after a valid btrbk command prefix, bypassing the allowlist and executing arbitrary commands with the privileges of the backup-target SSH account. Deployments that do not use ssh_filter_btrbk.sh in authorized_keys are not affected. This issue is fixed in version 0.32.7.",
"evidence": "osv:UBUNTU-CVE-2026-62943",
"products": [
{
"name": {
"value": "btrbk",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "0.19.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.20.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.21.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.22.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.22.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.22.2-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
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"evidence": "/affected/1/package/name"
},
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{
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"evidence": "/affected/1/versions"
},
{
"value": "0.26.0-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
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"evidence": "/affected/2/package/name"
},
"prerequisites": [],
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"affected_versions": [
{
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}
]
},
{
"name": {
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"evidence": "/affected/3/package/name"
},
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"affected_versions": [
{
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"evidence": "/affected/3/versions"
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{
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"evidence": "/affected/3/versions"
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]
},
{
"name": {
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},
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"affected_versions": [
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"evidence": "/affected/4/versions"
}
]
},
{
"name": {
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"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "0.32.6-2",
"evidence": "/affected/5/versions"
}
]
},
{
"name": {
"value": "btrbk",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "0.32.6-2",
"evidence": "/affected/6/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-62943",
"aliases": [
"UBUNTU-CVE-2026-62943"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "btrbk",
"purl": "pkg:deb/ubuntu/btrbk?arch=source&distro=xenial",
"ecosystem": "Ubuntu:16.04:LTS"
},
"versions": [
"0.19.3-1",
"0.20.0-1",
"0.21.0-1",
"0.22.0-1",
"0.22.1-1",
"0.22.2-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-62943.json"
},
"ecosystem_specific": {
"binaries": [
{
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}
]
}
},
{
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],
"package": {
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"purl": "pkg:deb/ubuntu/btrbk?arch=source&distro=bionic",
"ecosystem": "Ubuntu:18.04:LTS"
},
"versions": [
"0.25.1-1",
"0.26.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-62943.json"
},
"ecosystem_specific": {
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{
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}
]
}
},
{
"ranges": [
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}
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],
"package": {
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"purl": "pkg:deb/ubuntu/btrbk?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"0.27.1-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-62943.json"
},
"ecosystem_specific": {
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{
"binary_name": "btrbk",
"binary_version": "0.27.1-1"
}
]
}
},
{
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}
]
}
],
"package": {
"name": "btrbk",
"purl": "pkg:deb/ubuntu/btrbk?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"0.27.1-2",
"0.31.3-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-62943.json"
},
"ecosystem_specific": {
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},
{
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],
"package": {
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"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"0.32.5-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-62943.json"
},
"ecosystem_specific": {
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"binary_name": "btrbk",
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},
{
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],
"package": {
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"purl": "pkg:deb/ubuntu/btrbk?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"0.32.6-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-62943.json"
},
"ecosystem_specific": {
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{
"binary_name": "btrbk",
"binary_version": "0.32.6-2"
}
]
}
},
{
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{
"type": "ECOSYSTEM",
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}
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],
"package": {
"name": "btrbk",
"purl": "pkg:deb/ubuntu/btrbk?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"0.32.6-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-62943.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "btrbk",
"binary_version": "0.32.6-2"
}
]
}
}
],
"modified": "2026-10-17T13:00:31.407379517Z",
"provider": "osv",
"upstream": [
"CVE-2026-62943"
],
"references": [
"https://ubuntu.com/security/CVE-2026-62943",
"https://www.cve.org/CVERecord?id=CVE-2026-62943",
"https://github.com/digint/btrbk/security/advisories/GHSA-pf45-7g54-65h5",
"https://github.com/digint/btrbk/commit/29ca3c093205395bdeb9dd98677ab4139c458aec",
"https://github.com/digint/btrbk/releases/tag/v0.32.7"
]
},
"related_cves": [
{
"value": "CVE-2026-62943",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 360655,
"published_at": "2026-09-18T17:16:00+00:00"
}