CISCO Security Advisory
Published Date: Not specified
CVE: CVE-2026-20250
Advisory Summary
🏷️ 📣 🚨 Title: Cisco Secure Firewall 3100/4200 DTLS DoS Vulnerability (CVE-2026-20250)
🧩 What happened (brief):
Cisco disclosed a High impact vulnerability affecting Cisco Secure Firewall Adaptive Security Appliance (ASA) software and Cisco Secure Firewall Threat Defense (FTD) software on Secure Firewall 3100 and 4200 series devices. The issue is in DTLS (Datagram TLS) message handling, where improper resource management can be triggered.
- Unauthenticated, remote attacker can send a crafted stream of DTLS traffic
- Successful exploitation can cause the device to reload, resulting in a Denial of Service (DoS) condition
- DoS / service interruption (device reload)
- Likely operational disruption for perimeter security and traffic enforcement
- Cisco has released software updates to remediate the vulnerability
- Workarounds are also available (per Cisco advisory)
🛠️ Actionable recommendations for market & security teams:
1. Identify affected deployments: Check if your Secure Firewall 3100/4200 appliances run affected ASA/FTD versions.
2. Prioritize patching: Apply Cisco’s released updates as soon as operationally feasible (treat as High priority due to unauthenticated remote triggering and reload behavior).
3. Validate DTLS exposure: Review whether DTLS-dependent services or interfaces are externally reachable, and restrict exposure where possible.
4. Apply Cisco workarounds immediately if patching timelines are constrained, and monitor for DTLS traffic anomalies.
📎
-2026-20250