USN-8478-1

It was discovered that Ruby's Net::IMAP library did not properly verify that TLS encryption was started after issuing a STARTTLS command. A remote attacker could use this to perform a machine-in-the-middle attack and silently bypass TLS encryption. (CVE-2026-42246)

It was discovered that Ruby's Net::IMAP library did not validate string arguments passed to certain commands. A remote attacker could use this to inject arbitrary IMAP commands. (CVE-2026-42257)

It was discovered that Ruby's Net::IMAP library was vulnerable to a denial of service attack when authenticating with SCRAM-SHA1 or SCRAM-SHA256. A hostile server could send a very large iteration count value to cause excessive computation in the client. This issue only affected ruby3.3. (CVE-2026-42256)

References

Affected packages

Ubuntu:Pro:20.04:LTS / ruby2.7

Package

Name: ruby2.7
Purl: pkg:deb/ubuntu/ruby2.7?arch=source&distro=esm-infra%2Ffocal

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

2.7.0-5ubuntu1.18+esm5

Affected versions

2.*

2.7.0-1

2.7.0-2

2.7.0-3

2.7.0-4

2.7.0-4ubuntu1

2.7.0-5ubuntu1

2.7.0-5ubuntu1.1

2.7.0-5ubuntu1.2

2.7.0-5ubuntu1.3

2.7.0-5ubuntu1.4

2.7.0-5ubuntu1.5

2.7.0-5ubuntu1.6

2.7.0-5ubuntu1.7

2.7.0-5ubuntu1.8

2.7.0-5ubuntu1.9

2.7.0-5ubuntu1.10

2.7.0-5ubuntu1.11

2.7.0-5ubuntu1.12

2.7.0-5ubuntu1.13

2.7.0-5ubuntu1.14

2.7.0-5ubuntu1.15

2.7.0-5ubuntu1.16

2.7.0-5ubuntu1.17

2.7.0-5ubuntu1.18

2.7.0-5ubuntu1.18+esm1

2.7.0-5ubuntu1.18+esm3

2.7.0-5ubuntu1.18+esm4

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "libruby2.7",
            "binary_version": "2.7.0-5ubuntu1.18+esm5"
        },
        {
            "binary_name": "ruby2.7",
            "binary_version": "2.7.0-5ubuntu1.18+esm5"
        }
    ],
    "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-8478-1.json"

cves_map

{
    "ecosystem": "Ubuntu:Pro:20.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-42246",
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        },
        {
            "id": "CVE-2026-42257",
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        }
    ]
}

Ubuntu:22.04:LTS / ruby3.0

Package

Name: ruby3.0
Purl: pkg:deb/ubuntu/ruby3.0?arch=source&distro=jammy

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

3.0.2-7ubuntu2.13

Affected versions

3.*

3.0.2-5ubuntu1

3.0.2-7

3.0.2-7ubuntu2

3.0.2-7ubuntu2.1

3.0.2-7ubuntu2.2

3.0.2-7ubuntu2.3

3.0.2-7ubuntu2.4

3.0.2-7ubuntu2.5

3.0.2-7ubuntu2.6

3.0.2-7ubuntu2.7

3.0.2-7ubuntu2.8

3.0.2-7ubuntu2.10

3.0.2-7ubuntu2.11

3.0.2-7ubuntu2.12

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "libruby3.0",
            "binary_version": "3.0.2-7ubuntu2.13"
        },
        {
            "binary_name": "ruby3.0",
            "binary_version": "3.0.2-7ubuntu2.13"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8478-1.json"

cves_map

{
    "ecosystem": "Ubuntu:22.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-42246",
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        },
        {
            "id": "CVE-2026-42257",
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        }
    ]
}

Ubuntu:24.04:LTS / ruby3.2

Package

Name: ruby3.2
Purl: pkg:deb/ubuntu/ruby3.2?arch=source&distro=noble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

3.2.3-1ubuntu0.24.04.8

Affected versions

3.*

3.2.3-1

3.2.3-1build2

3.2.3-1build3

3.2.3-1ubuntu0.24.04.1

3.2.3-1ubuntu0.24.04.3

3.2.3-1ubuntu0.24.04.5

3.2.3-1ubuntu0.24.04.6

3.2.3-1ubuntu0.24.04.7

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "libruby3.2",
            "binary_version": "3.2.3-1ubuntu0.24.04.8"
        },
        {
            "binary_name": "ruby3.2",
            "binary_version": "3.2.3-1ubuntu0.24.04.8"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8478-1.json"

cves_map

{
    "ecosystem": "Ubuntu:24.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-42246",
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        },
        {
            "id": "CVE-2026-42257",
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        }
    ]
}

Ubuntu:26.04:LTS / ruby3.3

Package

Name: ruby3.3
Purl: pkg:deb/ubuntu/ruby3.3?arch=source&distro=resolute

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

3.3.8-2ubuntu3.1

Affected versions

3.*

3.3.8-2ubuntu2

3.3.8-2ubuntu3

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "libruby3.3",
            "binary_version": "3.3.8-2ubuntu3.1"
        },
        {
            "binary_name": "ruby3.3",
            "binary_version": "3.3.8-2ubuntu3.1"
        }
    ],
    "availability": "No subscription required"
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8478-1.json"

cves_map

{
    "ecosystem": "Ubuntu:26.04:LTS",
    "cves": [
        {
            "id": "CVE-2026-42246",
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        },
        {
            "id": "CVE-2026-42256",
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        },
        {
            "id": "CVE-2026-42257",
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ]
        }
    ]
}