Cisco Cyber Vision out-of-bounds write

CVSS Meta Temp Score
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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.
9.3$5k-$25k1.16+

Summaryinfo

A vulnerability was found in Cisco Cyber Vision, Secure Firewall Threat Defense Software and Snort. It has been declared as very critical. This vulnerability affects unknown code. The manipulation results in out-of-bounds write. This vulnerability was named CVE-2026-20043. The attack may be performed from remote. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Cisco Cyber Vision, Secure Firewall Threat Defense Software and Snort (version now known). It has been classified as very critical. Affected is some unknown processing. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. CWE is classifying the issue as CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20043 are related to issues concerning out-of-bounds writes that are grouped under the Common Weakness Enumeration (CWE) Base CWE-787.

The advisory is available at sec.cloudapps.cisco.com. This vulnerability is traded as CVE-2026-20043 since 10/08/2025. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 10/21/2026).

Upgrading eliminates this vulnerability.

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Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.5
VulDB Meta Temp Score: 9.3

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.0
CNA Vector (cisco): 🔒

CVSSv2info

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

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

10/08/2025 CVE reserved
10/21/2026 +378 days Advisory disclosed
10/21/2026 +0 days VulDB entry created
10/21/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: cisco.com

Advisory: sec.cloudapps.cisco.com
Status: Confirmed

CVE: CVE-2026-20043 (🔒)
GCVE (CVE): GCVE-0-2026-20043
GCVE (VulDB): GCVE-100-424878

Entryinfo

Created: 10/21/2026 18:43
Changes: 10/21/2026 18:43 (63)
Complete: 🔍
Cache ID: 216::103

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