# Cisco patches exploited flaw that can restart VPN firewalls

_Published Thursday, October 29, 2026 at 8:07 AM EDT · Security · Latest · Tier 2 — Notable_

![Cisco patches exploited flaw that can restart VPN firewalls — Primary](https://www.bleepstatic.com/content/hl-images/2026/10/29/Cisco-headpic.jpg)

Cisco released security updates for an actively exploited flaw that lets unauthenticated remote attackers crash firewalls running Adaptive Security Appliance or Threat Defense software. The vulnerability, CVE-2026-76418, causes unexpected device reloads and denial of service through crafted requests to the SSL remote access VPN.

Cisco attributes the flaw to logic errors when secondary authentication is configured on a tunnel group. Administrators unable to patch immediately can mitigate exposure by disabling secondary authentication on affected tunnel groups. Cisco has not identified the attackers or targeted organizations.

## Sources

- [BleepingComputer](https://www.bleepingcomputer.com/news/security/cisco-warns-of-firewall-zero-day-exploited-to-crash-ssl-vpn-devices/)

---
Canonical: https://techandbusiness.org/newswire/labQc6rHFt_rGYQu17sApf
Published: 2026-10-29T12:07:27.442Z
Story chronology: 2026-10-29T11:10:13.000Z
Retrieved: 2026-10-29T15:01:21.592Z
Publisher: Tech & Business (techandbusiness.org)