CVE-2026-20333

Cisco Secure Adaptive Security Appliance Software, Secure Firewall Threat Defense Software and Secure Firewall Management Center Software Hardening Release - Incorrect Comparison Vulnerabilities

Public exploit available. Not confirmed exploited in the wild yet. No fix published yet.

CVSS 3.18.8High EPSS percentile22nd0.3% chance in 30 days CISA KEVNot listedNo confirmed exploitation
Public exploit: 0 sources FixNone yetNo fix or workaround published

Published 2026-09-16Updated 2026-09-18Sources: CVE.org, NVD

NVD CVE.org

What to do

No fixed build or workaround is published yet. Limit exposure and watch for a patch.

Steps

Written by AI from the record

Check whether you run Cisco Secure Firewall ASA Software, Cisco Secure Firewall Threat Defense Software, or Cisco Secure Firewall Management Center Software, and identify every internet-reachable management system.
No fixed version has been published in the provided findings; ask Cisco or your managed IT provider for the vendor's remediation release and deployment timeline.
Until a fix is available, limit management access to trusted administrator networks, remove unnecessary low-level accounts, and review administrator activity for unexpected changes.

May need vendor or contractor work

Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense Software and Cisco Secure Firewall Management Center Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20333 are related to incorrect comparison conditions that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-697.

In plain language

Written by AI from the record

A serious flaw affects Cisco Secure Firewall ASA, FTD, and FMC software; businesses using these network-reachable systems should act now because a public exploit is available.

CVE-2026-20333 is a CVSS 8.8 incorrect-comparison vulnerability (CWE-697) in Cisco Secure Firewall ASA Software, FTD Software, and FMC that a low-privileged network attacker may use to compromise confidentiality, integrity, and availability.

If you're affected

Firewall administration compromise
Network security disruption
Sensitive data exposure
Service outages

What is it

This is a mistake in how affected Cisco security software checks certain conditions. Think of a security guard comparing the wrong details on an access pass: someone with limited access may be able to cause much greater damage than their pass should allow.

Who is affected

This matters if you run Cisco Secure Firewall ASA Software, Cisco Secure Firewall Threat Defense Software, or Cisco Secure Firewall Management Center Software. It is relevant to systems reachable over a network, and an attacker must already have a low-level login.

How urgent is it

A public exploit is available, so attackers do not need to develop their own method before attempting abuse. Treat this as urgent: reduce access to affected management systems now and obtain Cisco's remediation guidance without delay.

What to do — in detail

Confirm the installed software and release for every Cisco Secure Firewall ASA Software, Cisco Secure Firewall Threat Defense Software, and Cisco Secure Firewall Management Center Software deployment, with particular attention to management interfaces exposed beyond trusted administrator networks.

The supplied findings provide no affected-version range, fixed version, or branch-specific upgrade target. Contact Cisco support or your Cisco reseller for the applicable hardening/remediation release before scheduling an upgrade; validate the release in a non-production environment first because no compatibility or breaking-change information was supplied.

If patching is delayed, restrict management-plane access to dedicated administrator networks or a VPN, remove unneeded low-privilege accounts, enforce strong administrator authentication, and review configuration changes, account activity, and authentication events for unexpected behavior. This CVE is not listed in CISA KEV, so no CISA due date is provided.

Technical context

Severity is CVSS 3.1 8.8 (High): AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. The weakness is CWE-697, incorrect comparison. A public exploit is available, indicating weaponization, but the supplied findings do not confirm active exploitation and CISA KEV does not list this CVE. EPSS is 0.3% (25th percentile) with a flat trend; this is a prediction rather than evidence of exploitation. No patch information or fixed-version data is available in the findings.

This is a general assessment based on public vulnerability data. It does not account for your specific infrastructure — when in doubt, consult a security specialist.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS22nd

Public exploit

CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

0 sources with a proof of concept or module.

Exploit links, PoCs and Metasploit modules after sign-in

EPSS

0.3% chance of exploitation activity in the next 30 days, which ranks it in the 22nd percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

7 events over 2 days, from the signal feeds we watch.

2026-09-18Record updatedrecord updated
2026-09-17Record updatedrecord updated
2026-09-16Publishedweakness classified, record updated

Affected products

Ciscocommercial · USaka cisco systems, cisco systems inc.

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Scored 8.8 by NVD.

How it is reached

Attack Vector NetworkExploitable remotely over the network without any special conditions
Attack Complexity LowNo special conditions — the attack can be reliably reproduced
Privileges Required LowRequires basic user-level privileges
User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

Confidentiality HighTotal information disclosure — all data in the component is compromised
Integrity HighTotal loss of integrity — attacker can modify any data in the component
Availability HighTotal denial of service — the component is completely unavailable