Cyber Resilience

CVE-2026-20329

Published
16 September 2026
Modified
18 September 2026
CVSS Score v3.1 9.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.0045 38th percentile
Risk Priority 68 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-2026-20329 is a critical-severity Improper Check or Handling of Exceptional Conditions (CWE-703) vulnerability in Cisco Secure Adaptive (inferred from references). Its CVSS base score is 9.9 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 38th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-8 (Security and Privacy Engineering Principles) and SC-24 (Fail in Known State) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense Software and Cisco Secure Firewall Management Center Software engineering team has conducted a comprehensive internal security…

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review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-20329 are related to issues concerning improper handling of exceptional conditions that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-703.

CWE(s)
CWE-703

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-64435Shared CWE-703
CVE-2023-22413Shared CWE-703
CVE-2026-20187Shared CWE-703
CVE-2026-47316Shared CWE-703
CVE-2024-9104Shared CWE-703
CVE-2024-31883Shared CWE-703
CVE-2025-13026Shared CWE-703
CVE-2024-21525Shared CWE-703
CVE-2025-70758Shared CWE-703
CVE-2023-28959Shared CWE-703

Affected Assets

Cisco
Secure Adaptive
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-8 Security and Privacy Engineering Principles partial match

Requires application of security engineering principles that include robust exception and error handling during design.

SC-24 Fail in Known State partial match

Enforces failure to a known state while preserving required properties, limiting impact of unhandled exceptions.

SI-11 Error Handling partial match

Requires generation of safe, actionable error messages that directly addresses proper handling of exceptional conditions.

SI-17 Fail-safe Procedures partial match

Mandates explicit fail-safe procedures triggered by indicated failures, structurally preventing unhandled exceptional conditions.

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
prevents

Secure SDLC practices explicitly require anticipating and correctly handling exceptional conditions during design and coding.

References