Cisco Secure Firewall Adaptive Security Appliance Software OSPF Protocol integer overflow

Summaryinfo

A vulnerability marked as critical has been reported in Cisco Secure Firewall Adaptive Security Appliance Software and Secure Firewall Threat Defense Software. Affected by this vulnerability is an unknown functionality of the component OSPF Protocol Handler. The manipulation leads to integer overflow. This vulnerability is documented as CVE-2026-20025. The attack requires being on the local network. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Cisco Secure Firewall Adaptive Security Appliance Software and Secure Firewall Threat Defense Software (the affected version is unknown). It has been rated as critical. This issue affects an unknown code of the component OSPF Protocol Handler. The manipulation with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is availability. The summary by CVE is:

A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an authenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. To exploit this vulnerability, the attacker must have the OSPF secret key. This vulnerability is due to insufficient input validation when processing OSPF link-state update (LSU) packets. An attacker could exploit this vulnerability by sending crafted OSPF LSU packets. A successful exploit could allow the attacker to corrupt the heap, causing the device to reload, resulting in a DoS condition.

The advisory is shared at sec.cloudapps.cisco.com. The identification of this vulnerability is CVE-2026-20025 since 10/08/2025. The exploitation is known to be easy. The attack needs to be initiated within the local network. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 06/06/2026).

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Firewall Software

Vendor

• Cisco

Name

• Secure Firewall Adaptive Security Appliance Software
• Secure Firewall Threat Defense Software

License

• commercial

Website

• Vendor: https://www.cisco.com/

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