Is CVE-2026-20106 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-20106 being exploited in the wild.

How severe is CVE-2026-20106?

Medium severity, with a CVSS score of 5.3, published 4 March 2026.

Which products and versions are affected?

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software Multiple versions (see advisory for specific fixed releases); Cisco Secure Firewall Threat Defense (FTD) Software Multiple versions (see advisory for specific fixed releases).

Is there a fix for CVE-2026-20106?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-20106 attacked?

It is attacked over the network.

Am I affected by CVE-2026-20106?

Check whether you run Cisco Secure Firewall Adaptive Security Appliance (ASA) Software or Cisco Secure Firewall Threat Defense (FTD) Software at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-20106: Cisco Secure Firewall ASA and FTD SSL VPN denial of service

CVE-2026-20106 · Severity: medium · CVSS 5.3 · Published 2026-03-04

Cisco Secure Firewall appliances used to protect corporate networks include a Remote Access SSL VPN feature that is vulnerable to denial of service attacks. An unauthenticated attacker can send specially crafted packets to exhaust device memory, forcing the firewall to stop responding and require a manual reboot, thereby disrupting all protected traffic and network connectivity.

Technologies: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, Cisco Secure Firewall Threat Defense (FTD) Software. Vendors: Cisco.

Quick answers

Is CVE-2026-20106 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-20106 being exploited in the wild.
How severe is CVE-2026-20106?: Medium severity, with a CVSS score of 5.3, published 4 March 2026.
Which products and versions are affected?: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software Multiple versions (see advisory for specific fixed releases); Cisco Secure Firewall Threat Defense (FTD) Software Multiple versions (see advisory for specific fixed releases).
Is there a fix for CVE-2026-20106?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-20106 attacked?: It is attacked over the network.
Am I affected by CVE-2026-20106?: Check whether you run Cisco Secure Firewall Adaptive Security Appliance (ASA) Software or Cisco Secure Firewall Threat Defense (FTD) Software at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

CVE-2026-20106 is a denial of service vulnerability affecting the Remote Access SSL VPN, HTTP management server, and Mobile User Security (MUS) functionality in Cisco Secure Firewall ASA and FTD Software. The vulnerability exists due to insufficient validation of user-supplied input, allowing an unauthenticated, network-accessible attacker to send crafted packets that exhaust device memory. The flaw is rooted in improper bounds checking (CWE-120) and resource exhaustion (CWE-770). No authentication or user interaction is required; exploitation is achieved through direct network access to the SSL VPN service. A successful exploit causes the affected device to stop responding and requires a manual reboot to restore functionality. Cisco has released software updates to address this vulnerability; no workarounds are available.

Affected products

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software Multiple versions (see advisory for specific fixed releases)
Cisco Secure Firewall Threat Defense (FTD) Software Multiple versions (see advisory for specific fixed releases)

Timeline

2026-03-04: disclosed

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-vpn-m9sx6MbC

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