Cisco patches max-severity ISE flaw, the second critical zero-day this week
Cisco emergency-patched actively exploited CVE-2026-76460 (CVSS 10.0), an unauthenticated API flaw granting root on ISE appliances; CISA added it to KEV.
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CVE-2026-20079
Authentication bypass to root access in Cisco Secure Firewall Management Center
CISA: Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel Vulnerability
- CVSS 3.1
- 10.0 critical
- EPSS
- 88%p100
- Published
- ·
- Added to KEV
AI analysisSummaries by Vani AI
CVE-2026-20079 is an authentication bypass (CWE-288) in the web interface of Cisco Secure Firewall Management Center (FMC) Software, caused by an improper system process created at boot time. An unauthenticated, remote attacker can exploit it by sending crafted HTTP requests to the FMC web interface, which allows the execution of script files and commands on the device. A successful exploit grants the attacker root access to the underlying operating system, giving full control of the management platform (CVSS 3.1: 10.0, network-exploitable, no privileges or user interaction required, scope changed). The flaw affects Cisco Secure Firewall Management Center (FMC) and Security Cloud Control (SCC) Firewall Management deployments. Cisco has confirmed the vulnerability is being exploited in active attacks, it carries a 35.9% EPSS score (98th percentile), and CISA added it to the Known Exploited Vulnerabilities catalog on 2026-09-09.
What to do: Upgrade FMC (and SCC Firewall Management tenants) to the fixed release specified in Cisco's advisory, prioritizing internet-exposed or externally reachable management interfaces; CISA KEV action applies to federal agencies under BOD 26-04. Until patching, restrict FMC web interface access to trusted management networks and VPNs and check devices for signs of exploitation such as unexpected script execution, unfamiliar processes, or root-level changes. Triage per CISA's Forensics Triage Requirements if compromise is suspected.
| Product | Affected |
|---|---|
| Cisco Secure Firewall Management Center (FMC) Software (web interface) | — |
| Cisco Security Cloud Control (SCC) Firewall Management | — |
Estimated exposure
largeplausibly tens of thousands of FMC deployments worldwide (internet-exposed instances likely a smaller subset, likely thousands) — FMC is the centralized management hub for Cisco Secure Firewall (formerly Firepower), one of the largest enterprise firewall installed bases, but Cisco does not publish deployment counts and FMC web interfaces are frequently kept on…
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description · NVD
A vulnerability in the web interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to bypass authentication and execute script files on an affected device to obtain root access to the underlying operating system. This vulnerability is due to an improper system process that is created at boot time. An attacker could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute a variety of scripts and commands that allow root access to the device.
KEVCISA Known Exploited Vulnerability
- Affected
- Cisco Secure Firewall Management Center (FMC) and Security Cloud Control (SCC) Firewall Management
- Required action
- Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- Due date
- Ransomware use
- Unknown
- Vendors
- cisco
- Products
- secure firewall management center
- Weakness
- CWE-288
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
In the news
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Attackers Exploit Critical Cisco FMC Flaw to deploy Qilin ransomware
Three threat groups, including Qilin ransomware operators, exploit critical Cisco FMC flaws CVE-2026-20079 and CVE-2026-20316 for root access, credential theft, and ransomware.
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