CVE-2026-20131

Published Mar 4, 2026

Last updated 2 months ago

Exploit knownCVSS critical 10.0
AWS
Ubuntu
VPN
HTTP
Network
Tunneling protocol

Overview

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.
Source
psirt@cisco.com
NVD status
Analyzed
Products
secure_firewall_management_center

Risk scores

CVSS 3.1

Type
Secondary
Base score
10
Impact score
6
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Severity
CRITICAL

Known exploits

Data from CISA

Vulnerability name
Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability
Exploit added on
Mar 19, 2026
Exploit action due
Mar 22, 2026
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Weaknesses

psirt@cisco.com
CWE-502

Social media

Hype score
Not currently trending
  1. 🚨 THREAT INTEL | May 14, 2026 🔴 CRITICAL: CVE-2026-0300 Palo Alto RCE | CVE-2026-31431 Linux PrivEsc (due TOMORROW) | CVE-2026-20131 Cisco FMC RCE (ransomware) 🦠 Active: Mirai, Vidar, CobaltStrike, NWHStealer 🛡️ Block: 176.65.139.0/24 #CyberSecurity #ThreatIntel htt

    @404LABSx

    14 May 2026

    83 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  2. 🔴 Ransomware Intel WANNACRY Ransomware Gang: 33 New Victims Posted — Critical Infrastructure Targe… "CVE-2023-21529:** Microsoft Exchange Server Deserialization CVE-2026-20131:**…" 🔗 https://t.co/Po7R1rGfvC #CyberSecurity #ThreatIntel #ransomwaregang #wannacry #ra

    @SecurityAr58409

    29 Apr 2026

    48 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  3. Top 5 Trending CVEs: 1 - CVE-2024-32002 2 - CVE-2025-20333 3 - CVE-2026-20131 4 - CVE-2026-33626 5 - CVE-2024-57726 #cve #cvetrends #cveshield #cybersecurity https://t.co/4Fua3CAN6W

    @CVEShield

    27 Apr 2026

    313 Impressions

    0 Retweets

    1 Like

    0 Bookmarks

    0 Replies

    0 Quotes

  4. 🚨 THREAT INTEL Mar 25 | 🔴 CRITICAL RCE: Cisco FMC CVE-2026-20131 (ransomware active!) | 🟠 Patch TODAY: n8n CVE-2025-68613 | 🦠 Active: QakBot, Vidar, CobaltStrike | ⚠️ Russian APT hijacking Signal/WhatsApp | 🛡️ Block: 50.16.16.211 #CyberSecurity #ThreatIntel h

    @404LABSx

    25 Mar 2026

    125 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  5. Ip Protocol 1. KEV-DELTA SYNC (MAR 23): •CRITICAL: CISA added CVE-2025-32432 (Craft CMS) and CVE-2025-54068 (Laravel Livewire) to the KEV catalog on Friday, March 20. •PATCH DEADLINE: Federal agencies must remediate by April 3, 2026. •NEW ADDITION: CVE-2026-20131

    @SteveAJ777

    23 Mar 2026

    140 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  6. Three major Cisco management platform vulnerabilities in 2026. All in web interfaces. All CVSS 9+. CVE-2026-20131 (FMC) — CVSS 10, RCE as root CVE-2026-20127 (SD-WAN vManage) — RCE CVE-2023-20198 (IOS-XE web UI) — privilege escalation The pattern is undeniable: web-based

    @FirstPassLab

    21 Mar 2026

    47 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

Configurations