Cyber Resilience

CVE-2024-20402

Memory Safety in 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 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.0052 42th percentile
Risk Priority 63 floored blend · peak EPSS

Summary

CVE-2024-20402 is a high-severity Access of Memory Location After End of Buffer (CWE-788) vulnerability in Cisco Adaptive Security Appliance Software. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 42th 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-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A vulnerability in the SSL VPN feature for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of…

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service (DoS) condition. This vulnerability is due to a logic error in memory management when the device is handling SSL VPN connections. An attacker could exploit this vulnerability by sending crafted SSL/TLS packets to the SSL VPN server of the affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

CWE(s)

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.
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.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-20408Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20022Same product: Cisco Adaptive Security Appliance Software
CVE-2024-20494Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20049Same product: Cisco Adaptive Security Appliance Software
CVE-2025-20333Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20100Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20024Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20025Same product: Cisco Adaptive Security Appliance Software
CVE-2025-20182Same product: Cisco Adaptive Security Appliance Software
CVE-2026-20023Same 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

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.4.1

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover buffer-end violations through static analysis, fuzzing, or dynamic bounds checks.

Security engineering principles require bounds checking, safe arithmetic, and language choices that structurally eliminate post-end buffer accesses.

Input validation enforces bounds on lengths and indices before buffer operations, stopping out-of-bounds accesses after the end of the buffer.

Memory protection mechanisms limit the effects of post-end buffer accesses by blocking unauthorized code execution or data corruption.

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 mostly match
prevents

Secure SDLC practices directly require bounds checking and input validation that prevent out-of-bounds buffer accesses.

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.

finds

Security testing in development can detect buffer-overrun defects before release.

prevents

Secure development life cycle includes buffer-handling practices that reduce out-of-bounds accesses.

prevents

Application security requirements can mandate bounds checking and safe memory APIs.

prevents

Secure architecture principles discourage unsafe pointer arithmetic and unbounded buffers.

prevents

Secure coding standards directly forbid writing or reading past buffer ends.

References