VulnerabilityPublished 24 Apr 2024Updated 21 Oct 2025

CVE-2024-20359: Cisco Adaptive Security Appliance (ASA) Software · Code Injection

Affects Cisco Adaptive Security Appliance (ASA) SoftwareSource CVE Database V5

Exploited in the wild · KEV due 1 May 2024 · 18% EPSS : apply the vendor's fix or mitigations to Cisco Adaptive Security Appliance (ASA) Software now.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

6.0Medium

How severe the flaw is on the 0–10 CVSS scale.

KEV deadline: 1 May 2024 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
EPSS: 18.8% chance of exploitation in 30 days – higher than 97% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 24 Apr 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: evidence found.
Listed in CISA KEV the same day as disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

CVE ID reserved
by Cisco Systems, Inc.
8 Nov 202315:08 UTC, 168 days before disclosure
CVE published
on cve.org
24 Apr 202418:16 UTC, t = 0
Added to CISA KEV (opens in a new tab)
exploitation confirmed
24 Apr 2024, the same day as disclosure
KEV remediation due
US federal deadline
1 May 2024, 7 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Affected software

Product	Affected	Fixed in
Cisco Cisco Adaptive Security Appliance (ASA) Software	Affected 9.8.1 – 9.20.2 187 affected builds	Fixed in–

Check the firmware or software version for Cisco Adaptive Security Appliance (ASA) Software in the device's admin interface against the vendor advisory.

Description

A vulnerability in a legacy capability that allowed for the preloading of VPN clients and plug-ins and that has been available in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, local attacker to execute arbitrary code with root-level privileges. Administrator-level privileges are required to exploit this vulnerability. This vulnerability is due to improper validation of a file when it is read from system flash memory. An attacker could exploit this vulnerability by copying a crafted file to the disk0: file system of an affected device. A successful exploit could allow the attacker to execute arbitrary code on the affected device after the next reload of the device, which could alter system behavior. Because the injected code could persist across device reboots, Cisco has raised the Security Impact Rating (SIR) of this advisory from Medium to High.

Impact

The impact of CVE-2024-20359 is significant for organizations relying on Cisco ASA and FTD devices for network security, VPN access, and firewall functions. Successful exploitation grants root-level code execution, allowing attackers to fully compromise the device, modify configurations, intercept or redirect traffic, disable security controls, and maintain persistent access. This undermines the confidentiality and integrity of network traffic and security policies, potentially exposing sensitive data and enabling lateral movement within the network. Because the vulnerability requires administrator-level access, the initial compromise vector may be limited to insiders or attackers who have already breached administrative credentials. However, once exploited, the attacker gains persistent and powerful control over a critical security appliance, which can have cascading effects on the entire network security posture. The persistence of the injected code across reboots increases the difficulty of detection and remediation. Organizations with large deployments of affected Cisco ASA/FTD versions, especially in sectors with high security requirements such as finance, government, healthcare, and critical infrastructure, face elevated risk. The absence of known exploits in the wild currently reduces immediate threat but does not eliminate the risk of future exploitation.

Mitigation

To mitigate CVE-2024-20359, organizations should: 1) Immediately identify and inventory all Cisco ASA and FTD devices running affected software versions. 2) Apply Cisco's security patches or software updates that address this vulnerability as soon as they become available, prioritizing devices exposed to local administrative access. 3) Restrict local administrator access to trusted personnel only and enforce strong authentication mechanisms such as multi-factor authentication (MFA) for administrative accounts. 4) Monitor and audit file system changes on disk0: to detect unauthorized or suspicious file additions or modifications. 5) Implement strict access controls and network segmentation to limit the ability of attackers to gain local administrative access. 6) Regularly review and harden device configurations, disabling legacy features that are not in use, especially those related to VPN client preloading. 7) Employ host-based and network-based intrusion detection systems to identify anomalous behavior indicative of code injection or unauthorized reboots. 8) Maintain comprehensive logging and alerting on administrative actions and device reload events. 9) Conduct regular security assessments and penetration tests to validate the effectiveness of controls around Cisco ASA/FTD devices. 10) Educate administrators on the risks of this vulnerability and the importance of safeguarding privileged credentials.

CWE-94Improper Control of Generation of Code ('Code Injection') (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #10OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Architecture and Design · Refactoring
Refactor your program so that you do not have to dynamically generate code.
Architecture and Design
Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V5.2.8 (opens in a new tab)
V5.2.5 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
Leverage Executable Code in Non-Executable Files (opens in a new tab)
Manipulating User-Controlled Variables (opens in a new tab)
Code Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

Timeline

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Feb 2026, 09:03 UTC

WeaknessesCWE-94

Technical details

References

Community reviews

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