Cisco Secure Firewall Threat Defense Software Snort 3 VBA access of memory location before start of buffer

CVSS Meta Temp Score
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CTI Interest Score
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5.4$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Cisco Secure Firewall Threat Defense Software and UTD SNORT IPS Engine Software. This issue affects some unknown processing of the component Snort 3 VBA. Performing a manipulation results in access of memory location before start of buffer. This vulnerability is known as CVE-2026-20058. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Cisco Secure Firewall Threat Defense Software and UTD SNORT IPS Engine Software (affected version unknown). This affects an unknown functionality of the component Snort 3 VBA. The manipulation with an unknown input leads to a access of memory location before start of buffer vulnerability. CWE is classifying the issue as CWE-786. The product reads or writes to a buffer using an index or pointer that references a memory location prior to the beginning of the buffer. This is going to have an impact on availability. The summary by CVE is:

Multiple Cisco products are affected by vulnerabilities in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash. These vulnerabilities are due to improper error checking when decompressing VBA data. An attacker could exploit these vulnerabilities by sending crafted VBA data to the Snort 3 Detection Engine on the targeted device. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to unexpectedly restart, causing a DoS condition.

The advisory is shared at sec.cloudapps.cisco.com. This vulnerability is uniquely identified as CVE-2026-20058 since 10/08/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 311459 (Multiple Cisco Products Snort 3 VBA Decompression DoS (cisco-sa-ftd-snort3-vbavuls-96UcVVed)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (311459). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.4

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.8
CNA Vector (cisco): 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Access of memory location before start of buffer
CWE: CWE-786 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 311459
Nessus Name: Multiple Cisco Products Snort 3 VBA Decompression DoS (cisco-sa-ftd-snort3-vbavuls-96UcVVed)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

10/08/2025 CVE reserved
03/05/2026 +148 days Advisory disclosed
03/05/2026 +0 days VulDB entry created
05/02/2026 +58 days VulDB entry last update

Sourcesinfo

Vendor: cisco.com

Advisory: cisco-sa-ftd-snort3-vbavuls-96UcVVed
Status: Confirmed

CVE: CVE-2026-20058 (🔒)
GCVE (CVE): GCVE-0-2026-20058
GCVE (VulDB): GCVE-100-348825

Entryinfo

Created: 03/05/2026 02:33
Updated: 05/02/2026 11:02
Changes: 03/05/2026 02:33 (63), 05/02/2026 11:02 (2)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

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