Cyber Resilience

CVE-2024-20493

Cisco Adaptive Security Appliance Software 9.12.1 … 9.8.4.8

Published
23 October 2024
Modified
11 August 2026
Patch / advisory
CVSS Score v3.1 5.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS Score 0.0055 43th percentile
Risk Priority 45 floored blend · peak EPSS

Summary

CVE-2024-20493 is a medium-severity Missing Release of Resource after Effective Lifetime (CWE-772) vulnerability in Cisco Adaptive Security Appliance Software. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 43th 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-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A vulnerability in the login authentication functionality of the Remote Access SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to deny further VPN user authentications…

more

for several minutes, resulting in a temporary denial of service (DoS) condition. This vulnerability is due to ineffective handling of memory resources during the authentication process. An attacker could exploit this vulnerability by sending crafted packets, which could cause resource exhaustion of the authentication process. A successful exploit could allow the attacker to deny authentication for Remote Access SSL VPN users for several minutes, resulting in a temporary DoS condition.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

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.
T1499.002 Service Exhaustion Flood Impact
Adversaries may target the different network services provided by systems to conduct a denial of service (DoS).
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-20095Same product: Cisco Adaptive Security Appliance Software
CVE-2024-20481Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20082Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20106Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20105Same product: Cisco Adaptive Security Appliance Software
CVE-2023-20086Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20014Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20015Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20021Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20013Same product: Cisco Adaptive Security Appliance Software

Affected Assets

cisco
secure firewall threat defense
6.2.3, 6.2.3.1, 6.2.3.10, 6.2.3.11, 6.2.3.12
cisco
adaptive security appliance software
9.12.1, 9.12.1.2, 9.12.1.3, 9.12.2, 9.12.2.1

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover missing resource releases through dynamic analysis or stress testing.

Requiring documented development standards and tools can mandate explicit resource-release patterns in code.

Resource-quota allocation limits the blast radius of an unreleased-resource exhaustion condition.

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.

ID.AM-08 mostly match
prevents

Lifecycle management explicitly requires handling resources through end-of-life including release.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly prevent missing resource-release defects during development.

DE.CM-09 partial match
prevents

Runtime monitoring may surface resource-exhaustion symptoms but does not address release logic.

PR.IR-04 partial match
prevents

Capacity monitoring can detect exhaustion caused by unreleased resources but does not prevent the root defect.

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.

degrades

Explicit information-deletion requirements directly address timely release of resources after use.

prevents

Secure-SDLC practices include resource-management reviews, yet the control covers the entire lifecycle, not just this weakness.

prevents

Secure-coding rules can mandate explicit resource-release patterns, but the control is broader than this single weakness.

detects

Change-management processes may catch missing de-allocation during reviews, but the control itself does not target resource lifetime.

none

Configuration baselines can enforce resource limits or timeouts, indirectly reducing exposure to leaks.

References