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CVE-2026-76418: Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability

Headline from Cisco — Secure Firewall ASA Software and Cisco Secure FTD Software · compiled from 7 sources

According to BleepingComputer, Cisco has released security updates for a denial-of-service zero-day in its ASA and FTD firewall software that attackers are exploiting to crash vulnerable firewalls remotely.[1]

The Hacker News reports that the flaw, tracked as CVE-2026-76418, is rated 8.6 on the CVSS scoring system[2]. According to Cisco, the issue is rooted in the Remote Access SSL VPN service of ASA and FTD software.[2]Cisco said in its advisory that the bug is "due to logic errors when secondary authentication is configured on a tunnel group"[2]. The company also warned that "a successful VPN login is not required to reach the affected processing path."[3]SOC Prime reports that the flaw is categorized as CWE-690, which relates to an unchecked return value leading to a NULL pointer dereference[4].BleepingComputer reports that Cisco urged customers to patch after its Product Security Incident Response Team (PSIRT) discovered evidence that the flaw was being exploited in the wild earlier this month[1]. The outlet adds that Cisco hasn't shared additional information about the attacks, including which organizations are being targeted or who is exploiting the flaw[1].According to HOL Guard, CISA added the CVE to the Known Exploited Vulnerabilities catalog on 2026-10-29 with a 2026-11-01 due date[5].BleepingComputer cites Shadowserver as tracking more than 51,000 Cisco ASA SSL VPN devices exposed online[1].Security Online reports that Cisco's fix covers FTD versions 7.0.11, 7.2.13, 7.4.9, 7.6.7, 7.7.14, 10.0.3, and 10.1.1[6]. OpenVPN's blog, citing Cisco, says the available mitigations reduce the VPN's security posture[7].

Listen to the songCritical CVEs — October 30, 2026

Sources

  1. [1]New Cisco firewall zero-day exploited to crash SSL VPN devices
  2. [2]Cisco Patches Actively Exploited ASA and FTD VPN Flaw That Can Crash Firewalls
  3. [3]Cisco Fixes Second Exploited Firewall VPN Zero-Day Since August
  4. [4]CVE-2026-76418: Cisco Secure Firewall Zero-Day Exploited in SSL VPN Attacks
  5. [5]Cisco ASA and FTD SSL VPN crash bug exploited as a zero-day: unauthenticated reloads via secondary authentication (CVE-2026-76418, CISA KEV) | HOL Guard Threat Campaign
  6. [6]Cisco Secure Firewall Vulnerability Exploited in the Wild to Crash SSL VPN Devices
  7. [7]CVE-2026-76418: Cisco ASA/FTD SSL VPN DoS Under Active Exploitation

Every sentence here reports what a named outlet said, with a link to it. Compiled by 93 from the reporting below.

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CVE-2026-76418: Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability | 93