Security Digest · Vulnerability record · Known exploited
CVE-2026-76418: Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability
Exploited in the wild (CISA KEV). A vulnerability in the Remote Access SSL VPN service of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a…
CISA KEV · added 2026-10-29 CVSS 8.6 High EPSS 0.8% · p57 Check exposure
Should you act?
Exploited: patch now if you run it
CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Yes, if you run Cisco Secure Firewall ASA Software and Cisco Secure FTD Software. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-10-29, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-11-01; treat that as the outer limit, not the target.
- EPSS 0.8%, percentile 57: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 57% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Check exposure. Cisco ASA/FTD CVE-2026-76418: Exploited VPN Crash Bug — Only ASA and FTD headends that offer SSL remote access VPN with secondary authentication can be crashed, but that is being done in the wild, so those devices should be upgraded this week.
What it is
A vulnerability in the Remote Access SSL VPN service of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to logic errors when secondary authentication is configured on a tunnel group. An attacker could exploit this vulnerability by sending a crafted request when connecting to the SSL remote access VPN. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.
CISA’s 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.
Weakness type: CWE-690.
Product: Cisco Secure Firewall ASA Software and Cisco Secure FTD Software · Assigned by: cisco · Published: 2026-10-28
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Cisco | Cisco Secure Firewall Adaptive Security Appliance (ASA) Software | 9.16.1, 9.16.1.28, 9.16.2, 9.16.2.3, 9.16.2.7, 9.16.2.11, 9.16.2.13, 9.16.2.14, 9.16.3.3, 9.16.3, 9.16.3.14, 9.18.1 |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | 7.0.0, 7.0.0.1, 7.0.1, 7.0.1.1, 7.0.2, 7.2.0, 7.0.2.1, 7.0.3, 7.2.0.1, 7.0.4, 7.2.1, 7.0.5 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| cisco | 3.1 | 8.6 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: added 2026-10-29; federal due date 2026-11-01. Known ransomware use: Unknown.
- CISA required action: 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.
- CISA SSVC assessment: exploitation active, automatable yes, technical impact partial.
- FIRST EPSS (model of 2026-11-04): 0.82% probability of exploitation activity in the next 30 days; percentile 57.
Timeline
- — CVE record published by cisco
- — erroneo.us brief: Cisco ASA/FTD CVE-2026-76418: Exploited VPN Crash Bug
- — Added to CISA’s Known Exploited Vulnerabilities catalog
- — CVE record last updated
- — CISA remediation deadline for US federal agencies
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- Listed in CISA KEV notes (sec.cloudapps.cisco.com) sec.cloudapps.cisco.com
Vulnerability records
- CVE.org record CVE-2026-76418 cve.org
- NVD entry CVE-2026-76418 nvd.nist.gov
Government
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