CVE-2026-76418 Cisco Secure Firewall ASA Software and Cisco Secure FTD Software: memory-safety flaw
In plain words: The program mishandles the memory it uses to keep track of data. A specially made input can scramble that memory. Usually lets an attacker crash the program or run their own code with its permissions.
Confirmed exploited by CISA on · US federal patch deadline Nov 1, 2026
What to do
- Install Cisco's security update for Secure Firewall ASA Software and Cisco Secure FTD Software. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Patch edge devices first — attackers often start scanning for them within hours of a fix.
- Never expose the device's admin page to the internet.
- After patching a device that was exposed, follow the vendor's compromise checks, end active sessions and change passwords.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: They face the internet and guard the whole network, so a flaw here can hand attackers a way in — and these devices usually run no antivirus, so break-ins go unnoticed.
The details
- Official name
- Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability
- Product
- Cisco Secure Firewall ASA Software and Cisco Secure FTD Software
- CISA description
- 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.
- Type of flaw
- Memory-safety flaw (CWE-690)
- Confirmed exploited
- Oct 29, 2026
- US federal patch deadline
- Nov 1, 2026
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Answering about CVE-2026-76418 ·
Questions about CVE-2026-76418
Is CVE-2026-76418 being exploited?
Yes. CISA added CVE-2026-76418 to its Known Exploited Vulnerabilities catalog on Oct 29, 2026, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2026-76418?
Install Cisco's security update for Secure Firewall ASA Software and Cisco Secure FTD Software. If no update exists, follow the vendor's workaround or stop using the product until one ships. Patch edge devices first — attackers often start scanning for them within hours of a fix.
Am I affected by CVE-2026-76418?
Only if you use Cisco Secure Firewall ASA Software and Cisco Secure FTD Software. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.