UBUNTU-CVE-2025-24356

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Source
https://ubuntu.com/security/CVE-2025-24356
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-24356.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2025-24356
Upstream
Published
2025-01-27T18:15:00Z
Modified
2025-10-24T05:18:08Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:L CVSS Calculator
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

fastd is a VPN daemon which tunnels IP packets and Ethernet frames over UDP. When receiving a data packet from an unknown IP address/port combination, fastd will assume that one of its connected peers has moved to a new address and initiate a reconnect by sending a handshake packet. This "fast reconnect" avoids having to wait for a session timeout (up to ~90s) until a new connection is established. Even a 1-byte UDP packet just containing the fastd packet type header can trigger a much larger handshake packet (~150 bytes of UDP payload). Including IPv4 and UDP headers, the resulting amplification factor is roughly 12-13. By sending data packets with a spoofed source address to fastd instances reachable on the internet, this amplification of UDP traffic might be used to facilitate a Distributed Denial of Service attack. This vulnerability is fixed in v23.

References

Affected packages

Ubuntu:16.04:LTS / fastd

Package

Name
fastd
Purl
pkg:deb/ubuntu/fastd@17-4ubuntu0.1?arch=source&distro=xenial

Affected ranges

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

Affected versions

Other
17-4
17-4build1
17-4ubuntu0.*
17-4ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "17-4ubuntu0.1",
            "binary_name": "fastd"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-24356.json"

Ubuntu:18.04:LTS / fastd

Package

Name
fastd
Purl
pkg:deb/ubuntu/fastd@18-3ubuntu0.18.04.1?arch=source&distro=bionic

Affected ranges

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

Affected versions

Other
18-2
18-2ubuntu1
18-2ubuntu2
18-3
18-3ubuntu0.*
18-3ubuntu0.18.04.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "18-3ubuntu0.18.04.1",
            "binary_name": "fastd"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-24356.json"

Ubuntu:20.04:LTS / fastd

Package

Name
fastd
Purl
pkg:deb/ubuntu/fastd@18-3ubuntu0.1?arch=source&distro=focal

Affected ranges

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

Affected versions

Other
18-3build1
18-3ubuntu0.*
18-3ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "18-3ubuntu0.1",
            "binary_name": "fastd"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-24356.json"

Ubuntu:22.04:LTS / fastd

Package

Name
fastd
Purl
pkg:deb/ubuntu/fastd@22-2build1?arch=source&distro=jammy

Affected ranges

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

Affected versions

Other
21-1
22-2
22-2build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "22-2build1",
            "binary_name": "fastd"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-24356.json"

Ubuntu:24.04:LTS / fastd

Package

Name
fastd
Purl
pkg:deb/ubuntu/fastd@22-4build2?arch=source&distro=noble

Affected ranges

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

Affected versions

Other
22-4
22-4build1
22-4build2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "22-4build2",
            "binary_name": "fastd"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-24356.json"