UBUNTU-CVE-2026-39402

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Source

https://ubuntu.com/security/CVE-2026-39402

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39402.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-39402

Upstream

CVE-2026-39402

Published

2026-05-05T21:16:00Z

Modified

2026-05-20T16:25:38.695202580Z

Severity

4.3 (Medium) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:H CVSS Calculator
6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H CVSS Calculator
Ubuntu - medium

Summary

[none]

Details

lxc is a Linux container runtime. In the setuid helper lxc-user-nic, the delete path contains a logic flaw in the find_line() function that allows an unprivileged user to delete OVS-attached network interfaces belonging to other users. When lxc-user-nic delete scans its NIC database to authorize a deletion request, the interface name comparison can set the authorization flag based on a name match alone, even when the ownership, type, and link fields in that database entry belong to a different user. The vulnerable check sits after the goto next label handling, meaning it is reachable on lines where earlier ownership checks failed or were skipped. Because nothing downstream of this authorization signal re-verifies that the matched database line actually belongs to the caller, an unprivileged attacker with a valid lxc-usernet policy entry can trigger deletion of another user's OVS port on the same bridge. This is limited to multi-tenant environments using lxc-user-nic with OpenVSwitch bridges. The impact is denial of service - one tenant can repeatedly disconnect networking from containers run by another tenant on shared infrastructure. This is patched in version 7.0.0.

References

Affected packages

Ubuntu:14.04:LTS

lxc

Package

Name: lxc
Purl: pkg:deb/ubuntu/lxc?arch=source&distro=trusty

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.0.0~alpha1-0ubuntu11

1.0.0~alpha2-0ubuntu1

1.0.0~alpha2-0ubuntu3

1.0.0~alpha2-0ubuntu4

1.0.0~alpha2-0ubuntu5

1.0.0~alpha2-0ubuntu6

1.0.0~alpha3-0ubuntu1

1.0.0~alpha3-0ubuntu2

1.0.0~alpha3-0ubuntu3

1.0.0~alpha3-0ubuntu4

1.0.0~alpha3-0ubuntu5

1.0.0~alpha3-0ubuntu6

1.0.0~alpha3-0ubuntu7

1.0.0~alpha3-0ubuntu8

1.0.0~beta1-0ubuntu1

1.0.0~beta1-0ubuntu2

1.0.0~beta1-0ubuntu3

1.0.0~beta2-0ubuntu1

1.0.0~beta2-0ubuntu2

1.0.0~beta3-0ubuntu1

1.0.0~beta4-0ubuntu1

1.0.0~beta4-0ubuntu2

1.0.0~rc1-0ubuntu2

1.0.0~rc3-0ubuntu1

1.0.0~rc4-0ubuntu1

1.0.0-0ubuntu1

1.0.0-0ubuntu2

1.0.0-0ubuntu3

1.0.0-0ubuntu4

1.0.1-0ubuntu1

1.0.2-0ubuntu1

1.0.2-0ubuntu2

1.0.3-0ubuntu1

1.0.3-0ubuntu2

1.0.3-0ubuntu3

1.0.4-0ubuntu0.1

1.0.5-0ubuntu0.1

1.0.6-0ubuntu0.1

1.0.7-0ubuntu0.1

1.0.7-0ubuntu0.2

1.0.7-0ubuntu0.5

1.0.7-0ubuntu0.6

1.0.7-0ubuntu0.7

1.0.7-0ubuntu0.9

1.0.7-0ubuntu0.10

1.0.8-0ubuntu0.3

1.0.8-0ubuntu0.4

1.0.9-0ubuntu2

1.0.9-0ubuntu3

1.0.10-0ubuntu1

1.0.10-0ubuntu1.1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "liblxc1",
            "binary_version": "1.0.10-0ubuntu1.1"
        },
        {
            "binary_name": "lxc",
            "binary_version": "1.0.10-0ubuntu1.1"
        },
        {
            "binary_name": "lxc-templates",
            "binary_version": "1.0.10-0ubuntu1.1"
        },
        {
            "binary_name": "lxc-tests",
            "binary_version": "1.0.10-0ubuntu1.1"
        },
        {
            "binary_name": "python3-lxc",
            "binary_version": "1.0.10-0ubuntu1.1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39402.json"

Ubuntu:18.04:LTS

lxc

Package

Name: lxc
Purl: pkg:deb/ubuntu/lxc?arch=source&distro=bionic

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

2.*

2.1.0-0ubuntu1

2.1.1-0ubuntu1

3.*

3.0.0~beta1-0ubuntu3

3.0.0~beta2-0ubuntu2

3.0.0~beta3-0ubuntu1

3.0.0~beta4-0ubuntu1

3.0.0-0ubuntu1

3.0.0-0ubuntu2

3.0.1-0ubuntu1~18.04.1

3.0.1-0ubuntu1~18.04.2

3.0.2-0ubuntu1~18.04.1

3.0.3-0ubuntu1~18.04.1

3.0.3-0ubuntu1~18.04.3

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "liblxc-common",
            "binary_version": "3.0.3-0ubuntu1~18.04.3"
        },
        {
            "binary_name": "liblxc1",
            "binary_version": "3.0.3-0ubuntu1~18.04.3"
        },
        {
            "binary_name": "libpam-cgfs",
            "binary_version": "3.0.3-0ubuntu1~18.04.3"
        },
        {
            "binary_name": "lxc",
            "binary_version": "3.0.3-0ubuntu1~18.04.3"
        },
        {
            "binary_name": "lxc-utils",
            "binary_version": "3.0.3-0ubuntu1~18.04.3"
        },
        {
            "binary_name": "lxc1",
            "binary_version": "3.0.3-0ubuntu1~18.04.3"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39402.json"

Ubuntu:20.04:LTS

lxc

Package

Name: lxc
Purl: pkg:deb/ubuntu/lxc?arch=source&distro=focal

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

3.*

3.0.4-0ubuntu1

3.0.4-0ubuntu2

1:4.*

1:4.0.0-0ubuntu2

1:4.0.1-0ubuntu1

1:4.0.1-0ubuntu2

1:4.0.2-0ubuntu1

1:4.0.6-0ubuntu1~20.04.1

1:4.0.12-0ubuntu1~20.04.1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "liblxc-common",
            "binary_version": "1:4.0.12-0ubuntu1~20.04.1"
        },
        {
            "binary_name": "liblxc1",
            "binary_version": "1:4.0.12-0ubuntu1~20.04.1"
        },
        {
            "binary_name": "libpam-cgfs",
            "binary_version": "1:4.0.12-0ubuntu1~20.04.1"
        },
        {
            "binary_name": "lxc",
            "binary_version": "1:4.0.12-0ubuntu1~20.04.1"
        },
        {
            "binary_name": "lxc-utils",
            "binary_version": "1:4.0.12-0ubuntu1~20.04.1"
        },
        {
            "binary_name": "lxc1",
            "binary_version": "1:4.0.12-0ubuntu1~20.04.1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39402.json"

Ubuntu:22.04:LTS

lxc

Package

Name: lxc
Purl: pkg:deb/ubuntu/lxc?arch=source&distro=jammy

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1:4.*

1:4.0.10-0ubuntu5

1:4.0.12-0ubuntu1

1:4.0.12-0ubuntu2

1:5.*

1:5.0.0~git2209-g5a7b9ce67-0ubuntu1

1:5.0.0~git2209-g5a7b9ce67-0ubuntu1.1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "liblxc-common",
            "binary_version": "1:5.0.0~git2209-g5a7b9ce67-0ubuntu1.1"
        },
        {
            "binary_name": "liblxc1",
            "binary_version": "1:5.0.0~git2209-g5a7b9ce67-0ubuntu1.1"
        },
        {
            "binary_name": "libpam-cgfs",
            "binary_version": "1:5.0.0~git2209-g5a7b9ce67-0ubuntu1.1"
        },
        {
            "binary_name": "lxc",
            "binary_version": "1:5.0.0~git2209-g5a7b9ce67-0ubuntu1.1"
        },
        {
            "binary_name": "lxc-utils",
            "binary_version": "1:5.0.0~git2209-g5a7b9ce67-0ubuntu1.1"
        },
        {
            "binary_name": "lxc1",
            "binary_version": "1:5.0.0~git2209-g5a7b9ce67-0ubuntu1.1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39402.json"

Ubuntu:24.04:LTS

lxc

Package

Name: lxc
Purl: pkg:deb/ubuntu/lxc?arch=source&distro=noble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1:5.*

1:5.0.1-0ubuntu7

1:5.0.1-0ubuntu8

1:5.0.3-2ubuntu5

1:5.0.3-2ubuntu7

1:5.0.3-2ubuntu7.1

1:5.0.3-2ubuntu7.2

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "liblxc-common",
            "binary_version": "1:5.0.3-2ubuntu7.2"
        },
        {
            "binary_name": "liblxc1t64",
            "binary_version": "1:5.0.3-2ubuntu7.2"
        },
        {
            "binary_name": "libpam-cgfs",
            "binary_version": "1:5.0.3-2ubuntu7.2"
        },
        {
            "binary_name": "lxc",
            "binary_version": "1:5.0.3-2ubuntu7.2"
        },
        {
            "binary_name": "lxc-tests",
            "binary_version": "1:5.0.3-2ubuntu7.2"
        },
        {
            "binary_name": "lxc-utils",
            "binary_version": "1:5.0.3-2ubuntu7.2"
        },
        {
            "binary_name": "lxc1",
            "binary_version": "1:5.0.3-2ubuntu7.2"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39402.json"

Ubuntu:25.10

lxc

Package

Name: lxc
Purl: pkg:deb/ubuntu/lxc?arch=source&distro=questing

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1:6.*

1:6.0.3-1

1:6.0.4-2

1:6.0.4-3

1:6.0.4-4

1:6.0.4-4ubuntu1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "liblxc-common",
            "binary_version": "1:6.0.4-4ubuntu1"
        },
        {
            "binary_name": "liblxc1t64",
            "binary_version": "1:6.0.4-4ubuntu1"
        },
        {
            "binary_name": "libpam-cgfs",
            "binary_version": "1:6.0.4-4ubuntu1"
        },
        {
            "binary_name": "lxc",
            "binary_version": "1:6.0.4-4ubuntu1"
        },
        {
            "binary_name": "lxc-tests",
            "binary_version": "1:6.0.4-4ubuntu1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39402.json"

Ubuntu:26.04:LTS

lxc

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1:6.*

1:6.0.4-4ubuntu1

1:6.0.6-1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "liblxc-common",
            "binary_version": "1:6.0.6-1"
        },
        {
            "binary_name": "liblxc1t64",
            "binary_version": "1:6.0.6-1"
        },
        {
            "binary_name": "libpam-cgfs",
            "binary_version": "1:6.0.6-1"
        },
        {
            "binary_name": "lxc",
            "binary_version": "1:6.0.6-1"
        },
        {
            "binary_name": "lxc-tests",
            "binary_version": "1:6.0.6-1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39402.json"

Ubuntu:Pro:16.04:LTS

lxc

Package

Name: lxc
Purl: pkg:deb/ubuntu/lxc?arch=source&distro=esm-infra%2Fxenial

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.1.4-0ubuntu1

1.1.4-0ubuntu1.1

1.1.4-0ubuntu3

1.1.5-0ubuntu1

1.1.5-0ubuntu2

1.1.5-0ubuntu3

1.1.5-0ubuntu4

1.1.5-0ubuntu5

1.1.5-0ubuntu6

2.*

2.0.0~beta2-0ubuntu2

2.0.0~rc1-0ubuntu1

2.0.0~rc2-0ubuntu2

2.0.0~rc3-0ubuntu1

2.0.0~rc3-0ubuntu2

2.0.0~rc3-0ubuntu3

2.0.0~rc4-0ubuntu1

2.0.0~rc5-0ubuntu1

2.0.0~rc9-0ubuntu1

2.0.0~rc10-0ubuntu1

2.0.0~rc10-0ubuntu2

2.0.0~rc11-0ubuntu1

2.0.0~rc12-0ubuntu1

2.0.0~rc13-0ubuntu2

2.0.0~rc14-0ubuntu2

2.0.0~rc15-0ubuntu1

2.0.0-0ubuntu1

2.0.0-0ubuntu2

2.0.1-0ubuntu1~16.04.1

2.0.3-0ubuntu1~ubuntu16.04.1

2.0.4-0ubuntu1~ubuntu16.04.2

2.0.5-0ubuntu1~ubuntu16.04.1

2.0.5-0ubuntu1~ubuntu16.04.2

2.0.5-0ubuntu1~ubuntu16.04.3

2.0.6-0ubuntu1~ubuntu16.04.1

2.0.6-0ubuntu1~ubuntu16.04.2

2.0.7-0ubuntu1~16.04.1

2.0.7-0ubuntu1~16.04.2

2.0.8-0ubuntu1~16.04.2

2.0.11-0ubuntu1~16.04.3

2.0.11-0ubuntu1~16.04.3+esm1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "liblxc1",
            "binary_version": "2.0.11-0ubuntu1~16.04.3+esm1"
        },
        {
            "binary_name": "lua-lxc",
            "binary_version": "2.0.11-0ubuntu1~16.04.3+esm1"
        },
        {
            "binary_name": "lxc",
            "binary_version": "2.0.11-0ubuntu1~16.04.3+esm1"
        },
        {
            "binary_name": "lxc-common",
            "binary_version": "2.0.11-0ubuntu1~16.04.3+esm1"
        },
        {
            "binary_name": "lxc-templates",
            "binary_version": "2.0.11-0ubuntu1~16.04.3+esm1"
        },
        {
            "binary_name": "lxc-tests",
            "binary_version": "2.0.11-0ubuntu1~16.04.3+esm1"
        },
        {
            "binary_name": "lxc1",
            "binary_version": "2.0.11-0ubuntu1~16.04.3+esm1"
        },
        {
            "binary_name": "python3-lxc",
            "binary_version": "2.0.11-0ubuntu1~16.04.3+esm1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39402.json"