UBUNTU-CVE-2026-22701

filelock is a platform-independent file lock for Python. Prior to version 3.20.3, a TOCTOU race condition vulnerability exists in the SoftFileLock implementation of the filelock package. An attacker with local filesystem access and permission to create symlinks can exploit a race condition between the permission validation and file creation to cause lock operations to fail or behave unexpectedly. The vulnerability occurs in the acquire() method between raiseonnotwritable_file() (permission check) and os.open() (file creation). During this race window, an attacker can create a symlink at the lock file path, potentially causing the lock to operate on an unintended target file or leading to denial of service. This issue has been patched in version 3.20.3.

References

Affected packages

Ubuntu:Pro:18.04:LTS / python-filelock

Package

Name: python-filelock
Purl: pkg:deb/ubuntu/python-filelock@3.0.4-1ubuntu0.1~esm1?arch=source&distro=esm-apps/bionic

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

3.0.4-1ubuntu0.1~esm1

Affected versions

2.*

2.0.11-1

2.0.12-1

2.0.13-1

3.*

3.0.0-2

3.0.3-1

3.0.4-1

Ecosystem specific

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "python-filelock",
            "binary_version": "3.0.4-1ubuntu0.1~esm1"
        },
        {
            "binary_name": "python3-filelock",
            "binary_version": "3.0.4-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-22701.json"

Ubuntu:Pro:22.04:LTS / python-filelock

Package

Name: python-filelock
Purl: pkg:deb/ubuntu/python-filelock@3.6.0-1ubuntu0.1~esm1?arch=source&distro=esm-apps/jammy

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

3.6.0-1ubuntu0.1~esm1

Affected versions

3.*

3.0.12-2

3.3.2-1

3.4.0-1

3.4.2-1

3.4.2-2

3.6.0-1

Ecosystem specific

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "python3-filelock",
            "binary_version": "3.6.0-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-22701.json"

Ubuntu:Pro:24.04:LTS / python-filelock

Package

Name: python-filelock
Purl: pkg:deb/ubuntu/python-filelock@3.13.1-1ubuntu0.1~esm1?arch=source&distro=esm-apps/noble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

3.13.1-1ubuntu0.1~esm1

Affected versions

3.*

3.12.2-1

3.12.4-1

3.13.1-1

Ecosystem specific

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "python3-filelock",
            "binary_version": "3.13.1-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-22701.json"

Ubuntu:25.10 / python-filelock

Package

Name: python-filelock
Purl: pkg:deb/ubuntu/python-filelock@3.18.0-1?arch=source&distro=questing

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

3.*

3.18.0-1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "python3-filelock",
            "binary_version": "3.18.0-1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-22701.json"