VDB-348810 · CVE-2026-20020 · EUVD-2026-9477

Cisco Secure Firewall Threat Defense Software OSPF Protocol denial of service

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.5	$0-$5k	0.00

Summaryinfo

A vulnerability classified as critical was found in Cisco Secure Firewall Threat Defense Software. Affected by this vulnerability is an unknown functionality of the component OSPF Protocol Handler. The manipulation results in denial of service. This vulnerability is known as CVE-2026-20020. Access to the local network is required for this attack. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Cisco Secure Firewall Threat Defense Software (version unknown). It has been classified as critical. Affected is an unknown function of the component OSPF Protocol Handler. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. CVE summarizes:

A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. If OSPF authentication is enabled, the attacker must know the secret key to exploit this vulnerability. This vulnerability is due to insufficient input validation when processing OSPF update packets. An attacker could exploit this vulnerability by sending crafted OSPF update packets. A successful exploit could allow the attacker to create a buffer overflow, causing the affected device to reload, resulting in a DoS condition.

The advisory is available at sec.cloudapps.cisco.com. This vulnerability is traded as CVE-2026-20020. The exploitability is told to be easy. The attack needs to approached within the local network. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-9477). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Firewall Software

Vendor

Cisco

Name

Secure Firewall Threat Defense Software

License

commercial

Website

Vendor: https://www.cisco.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.2

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.7
NVD Vector: 🔒

CNA Base Score: 6.8
CNA Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

03/04/2026 Advisory disclosed
03/04/2026 +0 days VulDB entry created
05/05/2026 +62 days VulDB entry last update

Sourcesinfo

Vendor: cisco.com

Advisory: cisco-sa-asaftd-ospf-ZH8PhbSW
Status: Confirmed

CVE: CVE-2026-20020 (🔒)
GCVE (CVE): GCVE-0-2026-20020
GCVE (VulDB): GCVE-100-348810
EUVD: 🔒

Entryinfo

Created: 03/04/2026 19:00
Updated: 05/05/2026 16:33
Changes: 03/04/2026 19:00 (52), 03/05/2026 01:13 (1), 03/05/2026 03:02 (12), 05/05/2026 16:33 (11)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.