UBUNTU-CVE-2026-18477

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Source

https://ubuntu.com/security/CVE-2026-18477

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18477.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-18477

Upstream

CVE-2026-18477

Published

2026-08-03T17:16:00Z

Modified

2026-08-06T00:12:19Z

Severity

4.4 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N CVSS Calculator
Ubuntu - medium

Summary

[none]

Details

A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During restoration, files or directories may be created, renamed or overwritten outside the intended extraction directory. This could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does not require the attacker to modify or craft the archive, and standard backup and restore workflows—including extracting into a newly created directory without using the -P option do not mitigate the issue.

References

Affected packages

Ubuntu:22.04:LTS

tar

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.34+dfsg-1build1

1.34+dfsg-1build2

1.34+dfsg-1build3

1.34+dfsg-1ubuntu0.1.22.04.1

1.34+dfsg-1ubuntu0.1.22.04.2

1.34+dfsg-1ubuntu0.1.22.04.3

1.34+dfsg-1ubuntu0.1.22.04.4

1.34+dfsg-1ubuntu0.1.22.04.5

1.34+dfsg-1ubuntu0.1.22.04.6

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "tar",
            "binary_version": "1.34+dfsg-1ubuntu0.1.22.04.6"
        },
        {
            "binary_name": "tar-scripts",
            "binary_version": "1.34+dfsg-1ubuntu0.1.22.04.6"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18477.json"

Ubuntu:24.04:LTS

tar

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.34+dfsg-1.2ubuntu1

1.34+dfsg-1.2ubuntu2

1.34+dfsg-1.3ubuntu1

1.34+dfsg-1.4

1.35+dfsg-2~build1

1.35+dfsg-2

1.35+dfsg-3

1.35+dfsg-3build1

1.35+dfsg-3ubuntu0.1

1.35+dfsg-3ubuntu0.2

1.35+dfsg-3ubuntu0.3

1.35+dfsg-3ubuntu0.4

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "tar",
            "binary_version": "1.35+dfsg-3ubuntu0.4"
        },
        {
            "binary_name": "tar-scripts",
            "binary_version": "1.35+dfsg-3ubuntu0.4"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18477.json"

Ubuntu:26.04:LTS

tar

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.35+dfsg-3.1build1

1.35+dfsg-3.1build2

1.35+dfsg-4

1.35+dfsg-4ubuntu0.1

1.35+dfsg-4ubuntu0.2

1.35+dfsg-4ubuntu0.3

1.35+dfsg-4ubuntu0.4

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "tar",
            "binary_version": "1.35+dfsg-4ubuntu0.4"
        },
        {
            "binary_name": "tar-scripts",
            "binary_version": "1.35+dfsg-4ubuntu0.4"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18477.json"

Ubuntu:Pro:14.04:LTS

tar

Package

Name: tar
Purl: pkg:deb/ubuntu/tar?arch=source&distro=esm-infra-legacy%2Ftrusty

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.26+dfsg-8

1.27-3

1.27-4

1.27.1-1

1.27.1-1ubuntu0.1

1.27.1-1ubuntu0.1+esm1

1.27.1-1ubuntu0.1+esm2

1.27.1-1ubuntu0.1+esm3

1.27.1-1ubuntu0.1+esm4

1.27.1-1ubuntu0.1+esm5

1.27.1-1ubuntu0.1+esm6

1.27.1-1ubuntu0.1+esm7

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "tar",
            "binary_version": "1.27.1-1ubuntu0.1+esm7"
        },
        {
            "binary_name": "tar-scripts",
            "binary_version": "1.27.1-1ubuntu0.1+esm7"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18477.json"

Ubuntu:Pro:16.04:LTS

tar

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.27.1-2

1.28-2ubuntu1

1.28-2.1

1.28-2.1ubuntu0.1

1.28-2.1ubuntu0.2

1.28-2.1ubuntu0.2+esm1

1.28-2.1ubuntu0.2+esm2

1.28-2.1ubuntu0.2+esm3

1.28-2.1ubuntu0.2+esm4

1.28-2.1ubuntu0.2+esm5

1.28-2.1ubuntu0.2+esm6

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "tar",
            "binary_version": "1.28-2.1ubuntu0.2+esm6"
        },
        {
            "binary_name": "tar-scripts",
            "binary_version": "1.28-2.1ubuntu0.2+esm6"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18477.json"

Ubuntu:Pro:18.04:LTS

tar

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.29b-2

1.29b-2ubuntu0.1

1.29b-2ubuntu0.2

1.29b-2ubuntu0.3

1.29b-2ubuntu0.4

1.29b-2ubuntu0.4+esm1

1.29b-2ubuntu0.4+esm2

1.29b-2ubuntu0.4+esm3

1.29b-2ubuntu0.4+esm4

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "tar",
            "binary_version": "1.29b-2ubuntu0.4+esm4"
        },
        {
            "binary_name": "tar-scripts",
            "binary_version": "1.29b-2ubuntu0.4+esm4"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18477.json"

Ubuntu:Pro:20.04:LTS

tar

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.30+dfsg-6

1.30+dfsg-7

1.30+dfsg-7ubuntu0.20.04.1

1.30+dfsg-7ubuntu0.20.04.2

1.30+dfsg-7ubuntu0.20.04.3

1.30+dfsg-7ubuntu0.20.04.4

1.30+dfsg-7ubuntu0.20.04.4+esm1

1.30+dfsg-7ubuntu0.20.04.4+esm2

1.30+dfsg-7ubuntu0.20.04.4+esm3

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "tar",
            "binary_version": "1.30+dfsg-7ubuntu0.20.04.4+esm3"
        },
        {
            "binary_name": "tar-scripts",
            "binary_version": "1.30+dfsg-7ubuntu0.20.04.4+esm3"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18477.json"