Description
A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary Java code as root on an affected device.
This vulnerability is due to insecure deserialization of a user-supplied Java byte stream. An attacker could exploit this vulnerability by sending a crafted serialized Java object to the web-based management interface of an affected device. A successful exploit could allow the attacker to execute arbitrary code on the device and elevate privileges to root.
Note: If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Cisco | Cisco Secure Firewall Management Center (FMC) | 7.0.0, 7.0.0.1, 7.0.1, 7.1.0, 6.4.0.13, 7.0.1.1, 6.4.0.14, 7.1.0.1, 7.0.2, 6.4.0.15, 7.2.0, 7.0.2.1, 7.0.3, 7.1.0.2, 7.2.0.1, 7.0.4, 7.2.1, 7.0.5, 6.4.0.16, 7.3.0, 7.2.2, 7.3.1, 7.2.3, 7.1.0.3, 7.2.3.1, 7.2.4, 7.0.6, 7.2.4.1, 7.2.5, 7.3.1.1, 7.4.0, 6.4.0.17, 7.0.6.1, 7.2.5.1, 7.4.1, 7.2.6, 7.4.1.1,… | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
GitHub 6 repositories
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sak110/CVE-2026-20131 ★ 3 · Mar 11, 2026
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Hassan-Pouladi/Cisco-FMC-honeypot ★ 2 · Apr 7, 2026
Originally a Honeypot for CVE-2026-20131
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basesixtythree/B63-POC-CVE-2026-20131 ★ 0 · Oct 26, 2026
CVE-2026-20131 (Cisco FMC): pre-auth Java deserialization to root — VERIFIED-AT-PRIMITIVE showcase artifact (rebuilt twins; appliance not executed, entitlement-gated)
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Jwa7470/CVE-2026-20131-Post-Incident-Written-Report ★ 0 · Aug 28, 2026
Post-incident report on CVE-2026-20131 (CVSS 10.0), a Cisco FMC insecure deserialization vulnerability exploited by Interlock ransomware. Details root-cause analysis, lateral movement tactics, and em…
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ashrafzaryouh/CVE-2026-20131 ★ 0 · May 10, 2026
CVE-2026-20131
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p3Nt3st3r-sTAr/CVE-2026-20131-POC ★ 0 · Mar 6, 2026
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- WID-SEC-2026-0610 Cisco Secure Firewall Management Center: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 13, 2026
- NCSC-2026-0076 Kwetsbaarheden verholpen in Cisco Secure Firewall Management Center NCSC-NL (Netherlands) · Sep 12, 2026