UBUNTU-CVE-2026-96808
In Flatpak before 1.18.1, the revokefs writer, used by the flatpak-system-helper to receive repository data from unprivileged callers, validated file paths by rejecting literal .. components but did not prevent symlink traversal. A malicious local user in an active local session could obtain two revokefs sessions via the system helper, create a symlink in one session pointing into the other session's directory, and retain a file descriptor through that symlink. This allowed the attacker to modify files belonging to a different revokefs session after they had been validated and imported by the system helper. In particular, an attacker could use this to tamper with ostree commit objects in the system repository after they passed signature verification, enabling root-controlled file writes to attacker-chosen paths and local root privilege escalation.
UBUNTU-CVE-2026-96808
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:UBUNTU-CVE-2026-96808
flatpak
Source reference: /affected/0/package/name
- Affected versions
- 0.8.7-5
Source reference:
/affected/0/versions0.10.0-1Source reference:
/affected/0/versions0.10.0-2Source reference:
/affected/0/versions0.10.1-1Source reference:
/affected/0/versions0.10.2-1Source reference:
/affected/0/versions0.10.2.1-1Source reference:
/affected/0/versions0.10.2.1-2Source reference:
/affected/0/versions0.10.3-1Source reference:
/affected/0/versions0.11.1-0ubuntu1Source reference:
/affected/0/versions0.11.3-2Source reference:
/affected/0/versions0.11.3-3Source reference:
/affected/0/versions0.11.7-0ubuntu0.1Source reference:
/affected/0/versions1.0.1-0ubuntu0.1Source reference:
/affected/0/versions1.0.6-0ubuntu0.1Source reference:
/affected/0/versions1.0.7-0ubuntu0.18.04.1Source reference:
/affected/0/versions1.0.8-0ubuntu0.18.04.1Source reference:
/affected/0/versions1.0.9-0ubuntu0.1Source reference:
/affected/0/versions1.0.9-0ubuntu0.2Source reference:
/affected/0/versions1.0.9-0ubuntu0.3Source reference:
/affected/0/versions1.0.9-0ubuntu0.4Source reference:
/affected/0/versions1.0.9-0ubuntu0.4+esm1Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
flatpak
Source reference: /affected/1/package/name
- Affected versions
- 1.4.3-1
Source reference:
/affected/1/versions1.6.0-1Source reference:
/affected/1/versions1.6.1-1Source reference:
/affected/1/versions1.6.2-1Source reference:
/affected/1/versions1.6.3-1Source reference:
/affected/1/versions1.6.5-0ubuntu0.1Source reference:
/affected/1/versions1.6.5-0ubuntu0.2Source reference:
/affected/1/versions1.6.5-0ubuntu0.3Source reference:
/affected/1/versions1.6.5-0ubuntu0.4Source reference:
/affected/1/versions1.6.5-0ubuntu0.5Source reference:
/affected/1/versions1.6.5-0ubuntu0.5+esm1Source reference:
/affected/1/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
flatpak
Source reference: /affected/2/package/name
- Affected versions
- 1.10.2-3
Source reference:
/affected/2/versions1.12.2-1Source reference:
/affected/2/versions1.12.2-2Source reference:
/affected/2/versions1.12.3-1Source reference:
/affected/2/versions1.12.4-1Source reference:
/affected/2/versions1.12.5-1Source reference:
/affected/2/versions1.12.6-1Source reference:
/affected/2/versions1.12.7-1Source reference:
/affected/2/versions1.12.7-1ubuntu0.1Source reference:
/affected/2/versions1.12.7-1ubuntu0.1+esm1Source reference:
/affected/2/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
flatpak
Source reference: /affected/3/package/name
- Affected versions
- 1.14.4-2
Source reference:
/affected/3/versions1.14.5-1Source reference:
/affected/3/versions1.14.5-1build1Source reference:
/affected/3/versions1.14.5-1build4Source reference:
/affected/3/versions1.14.5-1build5Source reference:
/affected/3/versions1.14.5-1build6Source reference:
/affected/3/versions1.14.6-1Source reference:
/affected/3/versions1.14.6-1ubuntu0.1Source reference:
/affected/3/versions1.14.6-1ubuntu0.1+esm1Source reference:
/affected/3/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
flatpak
Source reference: /affected/4/package/name
- Affected versions
- 1.16.1-2ubuntu1
Source reference:
/affected/4/versions1.16.1-3ubuntu1Source reference:
/affected/4/versions1.16.2-1Source reference:
/affected/4/versions1.16.3-1Source reference:
/affected/4/versions1.16.3-1build1Source reference:
/affected/4/versions1.16.4-1Source reference:
/affected/4/versions1.16.4-2Source reference:
/affected/4/versions1.16.6-1Source reference:
/affected/4/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
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"events": [
{
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],
"package": {
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"purl": "pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Fbionic",
"ecosystem": "Ubuntu:Pro:18.04:LTS"
},
"versions": [
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"0.10.0-1",
"0.10.0-2",
"0.10.1-1",
"0.10.2-1",
"0.10.2.1-1",
"0.10.2.1-2",
"0.10.3-1",
"0.11.1-0ubuntu1",
"0.11.3-2",
"0.11.3-3",
"0.11.7-0ubuntu0.1",
"1.0.1-0ubuntu0.1",
"1.0.6-0ubuntu0.1",
"1.0.7-0ubuntu0.18.04.1",
"1.0.8-0ubuntu0.18.04.1",
"1.0.9-0ubuntu0.1",
"1.0.9-0ubuntu0.2",
"1.0.9-0ubuntu0.3",
"1.0.9-0ubuntu0.4",
"1.0.9-0ubuntu0.4+esm1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json"
},
"ecosystem_specific": {
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{
"binary_name": "flatpak",
"binary_version": "1.0.9-0ubuntu0.4+esm1"
},
{
"binary_name": "flatpak-tests",
"binary_version": "1.0.9-0ubuntu0.4+esm1"
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{
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{
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]
}
},
{
"ranges": [
{
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}
],
"package": {
"name": "flatpak",
"purl": "pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Ffocal",
"ecosystem": "Ubuntu:Pro:20.04:LTS"
},
"versions": [
"1.4.3-1",
"1.6.0-1",
"1.6.1-1",
"1.6.2-1",
"1.6.3-1",
"1.6.5-0ubuntu0.1",
"1.6.5-0ubuntu0.2",
"1.6.5-0ubuntu0.3",
"1.6.5-0ubuntu0.4",
"1.6.5-0ubuntu0.5",
"1.6.5-0ubuntu0.5+esm1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "flatpak",
"binary_version": "1.6.5-0ubuntu0.5+esm1"
},
{
"binary_name": "flatpak-tests",
"binary_version": "1.6.5-0ubuntu0.5+esm1"
},
{
"binary_name": "gir1.2-flatpak-1.0",
"binary_version": "1.6.5-0ubuntu0.5+esm1"
},
{
"binary_name": "libflatpak0",
"binary_version": "1.6.5-0ubuntu0.5+esm1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "flatpak",
"purl": "pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Fjammy",
"ecosystem": "Ubuntu:Pro:22.04:LTS"
},
"versions": [
"1.10.2-3",
"1.12.2-1",
"1.12.2-2",
"1.12.3-1",
"1.12.4-1",
"1.12.5-1",
"1.12.6-1",
"1.12.7-1",
"1.12.7-1ubuntu0.1",
"1.12.7-1ubuntu0.1+esm1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "flatpak",
"binary_version": "1.12.7-1ubuntu0.1+esm1"
},
{
"binary_name": "flatpak-tests",
"binary_version": "1.12.7-1ubuntu0.1+esm1"
},
{
"binary_name": "gir1.2-flatpak-1.0",
"binary_version": "1.12.7-1ubuntu0.1+esm1"
},
{
"binary_name": "libflatpak0",
"binary_version": "1.12.7-1ubuntu0.1+esm1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "flatpak",
"purl": "pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Fnoble",
"ecosystem": "Ubuntu:Pro:24.04:LTS"
},
"versions": [
"1.14.4-2",
"1.14.5-1",
"1.14.5-1build1",
"1.14.5-1build4",
"1.14.5-1build5",
"1.14.5-1build6",
"1.14.6-1",
"1.14.6-1ubuntu0.1",
"1.14.6-1ubuntu0.1+esm1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "flatpak",
"binary_version": "1.14.6-1ubuntu0.1+esm1"
},
{
"binary_name": "flatpak-tests",
"binary_version": "1.14.6-1ubuntu0.1+esm1"
},
{
"binary_name": "gir1.2-flatpak-1.0",
"binary_version": "1.14.6-1ubuntu0.1+esm1"
},
{
"binary_name": "libflatpak0",
"binary_version": "1.14.6-1ubuntu0.1+esm1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "flatpak",
"purl": "pkg:deb/ubuntu/flatpak?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"1.16.1-2ubuntu1",
"1.16.1-3ubuntu1",
"1.16.2-1",
"1.16.3-1",
"1.16.3-1build1",
"1.16.4-1",
"1.16.4-2",
"1.16.6-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "flatpak",
"binary_version": "1.16.6-1"
},
{
"binary_name": "flatpak-tests",
"binary_version": "1.16.6-1"
},
{
"binary_name": "gir1.2-flatpak-1.0",
"binary_version": "1.16.6-1"
},
{
"binary_name": "libflatpak0",
"binary_version": "1.16.6-1"
}
]
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #50910 · Revision 1
- Added to Heist Feed
- Publisher date