CVE-2026-20079
Act now ● On CISA KEV — actively exploited
Actively exploited — on the CISA KEV list.
CVSS base
10.0
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS — probability of exploitation (30 days)
75.8%
99.5th percentile
CISA KEV
Listed
Added 2026-09-09 · patch by 2026-09-12
Weakness / dates
CWE-288
Published 2026-03-04 · modified 2026-09-16
Description
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.
Affected
References
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-onprem-fmc-authbypass-5JPp45V2
- exploit http://seclists.org/fulldisclosure/2026/Aug/80
- exploit https://blog.talosintelligence.com/fmc-ongoing-exploitation/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20079