CVE-2026-20316: Cisco Secure Firewall Management Center Use of Hard-coded Password Vulnerability
Cisco Secure Firewall Management Center (FMC) formerly known as Firepower Management Center contains a use of hard-coded password vulnerability that 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.
Overview
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.
Vulnerability details
Cisco Secure Firewall Management Center (FMC) ships with a static, hard-coded password for a low-privileged account in its web interface. CWE-259 describes exactly this condition: a credential embedded in the software that cannot be changed through normal configuration and is identical across every affected deployment. Because the credential is fixed at the software level, any attacker who obtains it gains a valid authentication path regardless of the organization's password policies or access controls.
An attacker with network access to the FMC web interface submits the known static username and password to the login endpoint. No crafted payload beyond the credential itself is required. A successful login yields an authenticated session as the low-privileged user, with access to sensitive data on the device. Cisco's advisory explicitly notes that this foothold can be chained with other FMC software vulnerabilities to achieve privilege escalation, raising the practical severity above what the base score reflects. Attack surface is reduced when the FMC management interface is not internet-exposed, but any network path to the interface is sufficient.
Severity and impact
Exploitation status
This vulnerability is confirmed as actively exploited in the wild — it is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.
Detection and monitoring
- Run the vendor-specified CLI command in expert mode: zgrep "package_info.*license" /var/log/messages. Any output containing /var/tmp/license.tmp indicates the hard-coded credential was likely used to trigger that code path.
- Review FMC authentication logs for successful logins from the low-privileged static account originating from IP addresses outside your defined management network, particularly with no prior failed attempts.
Remediation
Additional hardening
- Restrict FMC management interface access to a dedicated out-of-band management network; block all internet-facing exposure at the perimeter firewall or ACL.
- Apply network-layer access controls (firewall rules or management-plane ACLs) limiting FMC web interface reachability to known administrator source addresses only.
- Treat any FMC instance that was internet-exposed before patching as potentially compromised; follow Cisco TAC forensic triage guidance before restoring to production.
- After applying the hot fix, audit FMC audit logs for historical logins from the static account to determine whether exploitation preceded remediation.
Key dates
References
Frequently asked questions
Does CVE-2026-20316 affect my FedRAMP authorization?
If Cisco Secure Firewall Management Center (FMC) runs inside your authorization boundary, yes. CVE-2026-20316 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, which carries a remediation deadline of August 1, 2026. For a FedRAMP-authorized service, an unpatched KEV in your boundary is a finding — one you either remediate or formally document a mitigation for before your assessor and sponsoring agency raise it.
How does Knox help me handle CVE-2026-20316?
Knox doesn't patch your software for you — remediating Cisco Secure Firewall Management Center (FMC) is your responsibility under the FedRAMP shared responsibility model. What Knox gives you is the pre-authorized, single-tenant boundary to remediate in, plus continuous compliance monitoring and audit-artifact coverage that help you document the fix for your next assessment. The fix is yours to apply; staying compliant while you apply it isn't something you manage alone.
How does Knox's monitoring help with vulnerabilities like this?
Knox's continuous monitoring, powered by KnoxAI, watches your environment in real time for newly disclosed vulnerabilities and compliance issues. Exposure surfaces as part of ongoing monitoring — not only when an assessor flags it at review time.
How do I get FedRAMP authorized with Knox?
Book a meeting and Knox maps your path — FedRAMP in 90 days for 90% less, without dependency or delay.
What happens if CVE-2026-20316 isn't remediated by August 1, 2026?
It becomes a POA&M item, and a growing POA&M list is what turns a routine continuous-monitoring review into a real conversation with your agency. Meeting the deadline keeps your authorization clean and the agency relationship intact.
What this vulnerability means for your FedRAMP compliance
Because this flaw is in CISA's Known Exploited Vulnerabilities catalog, FedRAMP continuous monitoring puts a hard remediation clock on it. The clock starts on awareness — and missing the deadline can put an Authority to Operate at risk.
FedRAMP remediation deadlines for actively exploited vulnerabilities
FedRAMP ConMon SLAs give cloud providers 30, 90, or 180 days by severity — but KEV-listed flaws carry the tighter CISA deadline shown above. For authorized services, that date is the compliance line that assessors and agency sponsors will check.
How Knox reduces the burden of CVE vulnerabilities
Remediating the flaw is your responsibility under the FedRAMP shared responsibility model — but staying compliant while you fix it isn't something you manage alone. KnoxAI's continuous monitoring surfaces exposure in real time, and Knox keeps your continuous-monitoring evidence and audit artifacts current while you apply the fix. Learn more about the Knox platform.
How to limit your exposure through inherited controls and isolation
Knox's single-tenant architecture gives every customer a dedicated boundary, and 60–80% of FedRAMP controls are inherited from the platform — shrinking the surface you have to patch and prove. See why teams choose Knox.
Ready to achieve FedRAMP authorization in 90 days or less?
Schedule a meeting to discuss scope, parse readiness, and map your company’s accelerated path to FedRAMP authorization.
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