UBUNTU-CVE-2026-96808

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Source
https://ubuntu.com/security/CVE-2026-96808
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-96808
Upstream
Published
2026-09-24T00:00:00Z
Modified
2026-09-25T06:37:26Z
Severity
  • 7.4 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:Pro:18.04:LTS / flatpak

Package

Name
flatpak
Purl
pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Fbionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.8.7-5
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.*
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

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "flatpak",
            "binary_version":  "1.0.9-0ubuntu0.4+esm1"
        },
        {
            "binary_name":  "flatpak-tests",
            "binary_version":  "1.0.9-0ubuntu0.4+esm1"
        },
        {
            "binary_name":  "gir1.2-flatpak-1.0",
            "binary_version":  "1.0.9-0ubuntu0.4+esm1"
        },
        {
            "binary_name":  "libflatpak0",
            "binary_version":  "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"

Ubuntu:Pro:20.04:LTS / flatpak

Package

Name
flatpak
Purl
pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Ffocal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
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

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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json"

Ubuntu:Pro:22.04:LTS / flatpak

Package

Name
flatpak
Purl
pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Fjammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
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

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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json"

Ubuntu:Pro:24.04:LTS / flatpak

Package

Name
flatpak
Purl
pkg:deb/ubuntu/flatpak?arch=source&distro=esm-apps%2Fnoble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
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

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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json"

Ubuntu:26.04:LTS / flatpak

Package

Name
flatpak
Purl
pkg:deb/ubuntu/flatpak?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
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

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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-96808.json"