# [CVE-2026-76418] Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability
**Severity:** HIGH | **CVSS Base Score:** 7.8 (3.1)
**CVSS Vector:** `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`
**EPSS Exploit Probability:** 0.82% (Percentile: 57.31%)
**CISA KEV (In The Wild):** YES (Due: 2026-11-01)
**Known Ransomware Campaigns:** Unknown
**Exploit Status:** active_wild
**Published:** 2026-10-29 | **Updated:** 2026-11-01

## Executive Summary
Cisco Secure Firewall ASA Software and Cisco Secure FTD Software contains an unchecked return value to NULL pointer dereference vulnerability that could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.

## Common Weakness Enumeration (CWE)
- **CWE-690**: Common Weakness Enumeration Flaw

## Affected Vendors & Products
- **Vendor:** Cisco | **Product:** Secure Firewall ASA Software and Cisco Secure FTD Software
  - **Affected Versions:** All vulnerable builds prior to vendor emergency patch
  - **Patched Version:** Refer to vendor advisory for patch release

## Technical Root Cause Analysis (AI Defense Agent)
Vulnerability in Secure Firewall ASA Software and Cisco Secure FTD Software allowing anomalous execution paths when processing untrusted input.

## Exploitation Mechanism & Attack Scenario
Threat actors issue specially crafted requests to the target service to exploit memory corruption or logic flaws.

## Enterprise Blast Radius
Potential unauthorized access, service disruption, and lateral movement within the perimeter.

## Remediation & Mitigation Playbook
1. 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.
2. Apply security updates according to vendor instructions.
3. Ensure network firewalls restrict exposure of administrative ports.

## Detection Guidance & Telemetry
Monitor endpoint execution logs and network traffic for unusual connections originating from Secure Firewall ASA Software and Cisco Secure FTD Software.

### Sigma Detection Rule
```yaml
title: Suspicious CVE-2026-76418 Activity
status: high
logsource:
  category: process_creation
detection:
  selection:
    CommandLine|contains: 'CVE-2026-76418'
  condition: selection
```


## References
- [CISA KEV Catalog Reference](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-76418) (cisa)
- [NVD Official Detail](https://nvd.nist.gov/vuln/detail/CVE-2026-76418) (advisory)