CVE-2023-20086

Cisco Adaptive Security Appliance Software 9.12.1 … 9.8.4.8

Published

01 November 2023

Modified

11 August 2026

Patch / advisory

View advisory

CVSS Score v3.1 8.6

Click a component to see what it means

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS Score 0.0065 50th percentile

Risk Priority 63 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-20086 is a high-severity Uncaught Exception (CWE-248) vulnerability in Cisco Adaptive Security Appliance Software. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Steganography (T1001.002); ranked in the top 50% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2023-24265

Vulnerability Data

A vulnerability in ICMPv6 processing of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper processing…

of ICMPv6 messages. An attacker could exploit this vulnerability by sending crafted ICMPv6 messages to a targeted Cisco ASA or FTD system with IPv6 enabled. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

CWE(s): CWE-248 NVD-CWE-noinfo

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.002 Steganography Command And Control

Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.

attack.mitre.org →

T1001.003 Protocol or Service Impersonation Command And Control

Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.

attack.mitre.org →

T1007 System Service Discovery Discovery

Adversaries may try to gather information about registered local system services.

attack.mitre.org →

T1016 System Network Configuration Discovery Discovery

Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.

attack.mitre.org →

T1020.001 Traffic Duplication Exfiltration

Adversaries may leverage traffic mirroring in order to automate data exfiltration over compromised infrastructure.

attack.mitre.org →

T1021 Remote Services Lateral Movement

Adversaries may use [Valid Accounts](https://attack.

attack.mitre.org →

Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-20353Same product: Cisco Adaptive Security Appliance Software

CVE-2026-20068Same product: Cisco Secure Firewall Threat Defense

CVE-2024-20426Same product: Cisco Adaptive Security Appliance Software

CVE-2026-20106Same product: Cisco Adaptive Security Appliance Software

CVE-2026-20013Same product: Cisco Adaptive Security Appliance Software

CVE-2026-20105Same product: Cisco Adaptive Security Appliance Software

CVE-2026-20021Same product: Cisco Adaptive Security Appliance Software

CVE-2024-20481Same product: Cisco Adaptive Security Appliance Software

CVE-2026-20014Same product: Cisco Adaptive Security Appliance Software

CVE-2023-20095Same product: Cisco Adaptive Security Appliance Software

Affected Assets

cisco

adaptive security appliance software

9.12.1, 9.12.1.2, 9.12.1.3, 9.12.2, 9.12.2.1

cisco

secure firewall threat defense

6.2.3, 6.2.3.1, 6.2.3.10, 6.2.3.11, 6.2.3.12

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-24 Fail in Known State

addresses: CWE-248

Prevents abrupt termination from uncaught exceptions by requiring a defined, preserved-state failure mode.

SI-17 Fail-safe Procedures

addresses: CWE-248

Requires pre-defined safe responses for uncaught exceptions so they do not result in undefined or insecure program termination.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 partial match

blocks

Secure SDLC practices explicitly require structured exception handling to prevent uncaught exceptions from reaching production.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match

removes

A.5.15 Access control partial match

removes

A.5.16 Identity management partial match

removes

A.5.17 Authentication information partial match

removes

A.5.18 Access rights partial match

removes

A.8.10 Information deletion partial match

removes