UBUNTU-CVE-2026-3706

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Source
https://ubuntu.com/security/CVE-2026-3706
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-3706.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-3706
Upstream
Published
2026-03-08T05:16:00Z
Modified
2026-05-20T16:25:37.256719025Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
  • 1.7 (Low) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

A vulnerability was determined in mkj Dropbear up to 2025.89. Impacted is the function unpackneg of the file src/curve25519.c of the component S Range Check. This manipulation causes improper verification of cryptographic signature. The attack can be initiated remotely. The attack is considered to have high complexity. The exploitability is considered difficult. The actual existence of this vulnerability is currently in question. Patch name: fdec3c90a15447bd538641d85e5a3e3ac981011d. To fix this issue, it is recommended to deploy a patch. The project maintainer explains: "Signature Malleability is not exploitable in SSH protocol. (...) [A] PoC doesn't exist for SSH implementation, but rather it's against the internal API."

References

Affected packages

Ubuntu:16.04:LTS
dropbear

Package

Name
dropbear
Purl
pkg:deb/ubuntu/dropbear?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2014.*
2014.65-1ubuntu2
2015.*
2015.68-1
2015.70-1
2015.71-1
2016.*
2016.72-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dropbear",
            "binary_version": "2016.72-1"
        },
        {
            "binary_name": "dropbear-bin",
            "binary_version": "2016.72-1"
        },
        {
            "binary_name": "dropbear-initramfs",
            "binary_version": "2016.72-1"
        },
        {
            "binary_name": "dropbear-run",
            "binary_version": "2016.72-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-3706.json"
Ubuntu:22.04:LTS
dropbear

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2020.*
2020.81-3
2020.81-4
2020.81-5
2020.81-5ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dropbear",
            "binary_version": "2020.81-5ubuntu0.1"
        },
        {
            "binary_name": "dropbear-bin",
            "binary_version": "2020.81-5ubuntu0.1"
        },
        {
            "binary_name": "dropbear-initramfs",
            "binary_version": "2020.81-5ubuntu0.1"
        },
        {
            "binary_name": "dropbear-run",
            "binary_version": "2020.81-5ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-3706.json"
Ubuntu:24.04:LTS
dropbear

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2022.*
2022.83-2
2022.83-3
2022.83-4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dropbear",
            "binary_version": "2022.83-4"
        },
        {
            "binary_name": "dropbear-bin",
            "binary_version": "2022.83-4"
        },
        {
            "binary_name": "dropbear-initramfs",
            "binary_version": "2022.83-4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-3706.json"
Ubuntu:25.10
dropbear

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2024.*
2024.86-2
2025.*
2025.88-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dropbear",
            "binary_version": "2025.88-2"
        },
        {
            "binary_name": "dropbear-bin",
            "binary_version": "2025.88-2"
        },
        {
            "binary_name": "dropbear-initramfs",
            "binary_version": "2025.88-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-3706.json"
Ubuntu:26.04:LTS
dropbear

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2025.*
2025.88-2
2025.89-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dropbear",
            "binary_version": "2025.89-1"
        },
        {
            "binary_name": "dropbear-bin",
            "binary_version": "2025.89-1"
        },
        {
            "binary_name": "dropbear-initramfs",
            "binary_version": "2025.89-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-3706.json"
Ubuntu:Pro:18.04:LTS
dropbear

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2017.*
2017.75-2
2017.75-3build1
2017.75-3ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dropbear",
            "binary_version": "2017.75-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "dropbear-bin",
            "binary_version": "2017.75-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "dropbear-initramfs",
            "binary_version": "2017.75-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "dropbear-run",
            "binary_version": "2017.75-3ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-3706.json"
Ubuntu:Pro:20.04:LTS
dropbear

Package

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

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2019.*
2019.78-2build1
2019.78-2ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "dropbear",
            "binary_version": "2019.78-2ubuntu0.1~esm1"
        },
        {
            "binary_name": "dropbear-bin",
            "binary_version": "2019.78-2ubuntu0.1~esm1"
        },
        {
            "binary_name": "dropbear-initramfs",
            "binary_version": "2019.78-2ubuntu0.1~esm1"
        },
        {
            "binary_name": "dropbear-run",
            "binary_version": "2019.78-2ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-3706.json"