USN-8447-3

USN-8447-1 fixed vulnerabilities in Go Cryptography. This update provides the corresponding updates for Go Cryptography code embedded in Google Guest Agent.

Original advisory details:

It was discovered that Go Cryptography did not properly handle SSH global request responses. A remote attacker could possibly use this issue to cause a denial of service. (CVE-2026-39830)

It was discovered that Go Cryptography did not properly verify user presence when using FIDO/U2F security keys. An attacker could possibly use this issue to bypass user presence verification for hardware security keys. This issue only affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-39831)

It was discovered that Go Cryptography did not properly serialize SSH agent key constraint extensions. An attacker could possibly use this issue to bypass intended key usage restrictions. This issue only affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-39832)

It was discovered that Go Cryptography did not properly enforce the confirm-before-use constraint in the SSH agent keyring. An attacker could possibly use this issue to use SSH keys without the required user confirmation. (CVE-2026-39833)

It was discovered that Go Cryptography had an integer overflow when handling large SSH channel writes. A remote attacker could possibly use this issue to cause a denial of service. (CVE-2026-39834)

It was discovered that Go Cryptography did not properly check certificate authority key revocation. An attacker could possibly use this issue to bypass certificate authority revocation checks. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-42508)

It was discovered that Go Cryptography did not properly enforce the source- address critical option for all SSH server callback types. An attacker could possibly use this issue to bypass source address authorization restrictions. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-46595)

References

Affected packages

Ubuntu:22.04:LTS

google-guest-agent

Package

Name: google-guest-agent
Purl: pkg:deb/ubuntu/google-guest-agent?arch=source&distro=jammy

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

20250116.00-0ubuntu1~22.04.3

Affected versions

20210629.*

20210629.00-0ubuntu1

20210629.00-0ubuntu2

20220104.*

20220104.00-0ubuntu1

20220104.00-0ubuntu2

20220622.*

20220622.00-0ubuntu2~22.04.0

20220622.00-0ubuntu2~22.04.1

20230426.*

20230426.00-0ubuntu2~22.04.0

20231004.*

20231004.02-0ubuntu1~22.04.1

20231004.02-0ubuntu1~22.04.2

20231004.02-0ubuntu1~22.04.3

20231004.02-0ubuntu1~22.04.4

20231004.02-0ubuntu1~22.04.5

20240716.*

20240716.00-0ubuntu1~22.04.0

20241011.*

20241011.01-0ubuntu1~22.04.0

20250116.*

20250116.00-0ubuntu1~22.04.0

20250116.00-0ubuntu1~22.04.1

20250116.00-0ubuntu1~22.04.2

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20250116.00-0ubuntu1~22.04.3"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8447-3.json"

cves_map

{
    "ecosystem": "Ubuntu:22.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-39830",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39831",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39834",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}

Ubuntu:24.04:LTS

google-guest-agent

Package

Name: google-guest-agent
Purl: pkg:deb/ubuntu/google-guest-agent?arch=source&distro=noble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

20250116.00-0ubuntu1~24.04.4

Affected versions

20230426.*

20230426.00-0ubuntu3

20231004.*

20231004.02-0ubuntu1

20231004.02-0ubuntu3

20240213.*

20240213.00-0ubuntu1

20240213.00-0ubuntu2

20240213.00-0ubuntu3

20240213.00-0ubuntu3.1

20240213.00-0ubuntu3.2

20240716.*

20240716.00-0ubuntu1~24.04.0

20240716.00-0ubuntu1~24.04.1

20241011.*

20241011.01-0ubuntu1~24.04.0

20250116.*

20250116.00-0ubuntu1~24.04.0

20250116.00-0ubuntu1~24.04.1

20250116.00-0ubuntu1~24.04.2

20250116.00-0ubuntu1~24.04.3

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20250116.00-0ubuntu1~24.04.4"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8447-3.json"

cves_map

{
    "ecosystem": "Ubuntu:24.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-39830",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39831",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39834",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-46595",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}

Ubuntu:25.10

google-guest-agent

Package

Name: google-guest-agent
Purl: pkg:deb/ubuntu/google-guest-agent?arch=source&distro=questing

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

20250506.01-0ubuntu1.2

Affected versions

20250116.*

20250116.00-0ubuntu2

20250506.*

20250506.01-0ubuntu1

20250506.01-0ubuntu1.1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20250506.01-0ubuntu1.2"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8447-3.json"

cves_map

{
    "ecosystem": "Ubuntu:25.10",
    "cves": [
        {
            "id": "CVE-2026-39830",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39831",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39834",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-46595",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}

Ubuntu:26.04:LTS

google-guest-agent

Package

Name: google-guest-agent
Purl: pkg:deb/ubuntu/google-guest-agent?arch=source&distro=resolute

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

20250506.01-0ubuntu2.1

Affected versions

20250506.*

20250506.01-0ubuntu1

20250506.01-0ubuntu2

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20250506.01-0ubuntu2.1"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8447-3.json"

cves_map

{
    "ecosystem": "Ubuntu:26.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-39830",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39831",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39834",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-46595",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}

Ubuntu:Pro:16.04:LTS

google-guest-agent

Package

Name: google-guest-agent
Purl: pkg:deb/ubuntu/google-guest-agent?arch=source&distro=esm-apps-legacy%2Fxenial

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

20240716.00-0ubuntu1~16.04.0+esm3

Affected versions

20201217.*

20201217.02-0ubuntu1~16.04.0

20230426.*

20230426.00-0ubuntu2~16.04.3

20231004.*

20231004.02-0ubuntu1~16.04.1

20231004.02-0ubuntu1~16.04.2

20240716.*

20240716.00-0ubuntu1~16.04.0

20240716.00-0ubuntu1~16.04.0+esm1

20240716.00-0ubuntu1~16.04.0+esm2

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20240716.00-0ubuntu1~16.04.0+esm3"
        }
    ],
    "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8447-3.json"

cves_map

{
    "ecosystem": "Ubuntu:Pro:16.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-39830",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39831",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39834",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}

Ubuntu:Pro:18.04:LTS

google-guest-agent

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

20241011.01-0ubuntu1~18.04.0+esm3

Affected versions

20201217.*

20201217.02-0ubuntu1~18.04.0

20210414.*

20210414.00-0ubuntu1~18.04.0

20210629.*

20210629.00-0ubuntu1~18.04.1

20220622.*

20220622.00-0ubuntu2~18.04.0

20220622.00-0ubuntu2~18.04.1

20230426.*

20230426.00-0ubuntu2~18.04.0

20231004.*

20231004.02-0ubuntu1~18.04.2

20231004.02-0ubuntu1~18.04.3

20240716.*

20240716.00-0ubuntu1~18.04.0

20241011.*

20241011.01-0ubuntu1~18.04.0

20241011.01-0ubuntu1~18.04.0+esm1

20241011.01-0ubuntu1~18.04.0+esm2

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20241011.01-0ubuntu1~18.04.0+esm3"
        }
    ],
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8447-3.json"

cves_map

{
    "ecosystem": "Ubuntu:Pro:18.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-39830",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39831",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39834",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}

Ubuntu:Pro:20.04:LTS

google-guest-agent

Package

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

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

20250116.00-0ubuntu1~20.04.0+esm3

Affected versions

20201217.*

20201217.02-0ubuntu1~20.04.0

20210414.*

20210414.00-0ubuntu1~20.04.0

20210629.*

20210629.00-0ubuntu1~20.04.0

20220622.*

20220622.00-0ubuntu2~20.04.0

20220622.00-0ubuntu2~20.04.2

20230426.*

20230426.00-0ubuntu2~20.04.0

20231004.*

20231004.02-0ubuntu1~20.04.1

20231004.02-0ubuntu1~20.04.2

20231004.02-0ubuntu1~20.04.3

20231004.02-0ubuntu1~20.04.4

20240716.*

20240716.00-0ubuntu1~20.04.0

20241011.*

20241011.01-0ubuntu1~20.04.1

20250116.*

20250116.00-0ubuntu1~20.04.0

20250116.00-0ubuntu1~20.04.0+esm1

20250116.00-0ubuntu1~20.04.0+esm2

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20250116.00-0ubuntu1~20.04.0+esm3"
        }
    ],
    "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8447-3.json"

cves_map

{
    "ecosystem": "Ubuntu:Pro:20.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-39830",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39831",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        },
        {
            "id": "CVE-2026-39834",
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ]
        }
    ]
}