CVE-2024-23304VulnerabilityPublished 6 Feb 2024Updated 4 Jun 2025

CVE-2024-23304: Cybozu KUNAI for Android · Denial-of-service (DoS)

Affects Cybozu KUNAI for AndroidSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
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: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Feb 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: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

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 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

Affected software

Product	Affected	Fixed in
Cybozu, Inc. Cybozu KUNAI for Android	Affected >=3.0.20 <=3.0.21	Fixed in–

AI-suggested

Given the absence of an official patch at the time of reporting, European organizations should implement targeted mitigations beyond generic advice. First, restrict network access to Cybozu KUNAI services by enforcing IP whitelisting or VPN-only access to reduce exposure to untrusted networks. Employ network-level intrusion detection and prevention systems (IDS/IPS) to monitor and block anomalous traffic patterns that may trigger the DoS condition. Organizations should also consider deploying mobile device management (MDM) solutions to control application versions and enforce updates once patches become available. Temporary disabling or limiting the use of Cybozu KUNAI on Android devices in high-risk environments may be warranted until a fix is released. Additionally, maintain comprehensive monitoring of application availability and implement alerting for service disruptions to enable rapid incident response. Coordination with Cybozu, Inc. for timely patch deployment is critical. Finally, educate IT staff and users about the vulnerability and encourage vigilance against unusual application behavior.

Description

Cybozu KUNAI for Android 3.0.20 to 3.0.21 allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition by performing certain operations.

Impact

For European organizations, the impact of this DoS vulnerability can be significant, especially for enterprises relying on Cybozu KUNAI for secure remote access to internal systems. A successful exploitation could disrupt employee access to critical corporate resources, leading to operational downtime, reduced productivity, and potential delays in business processes. While the vulnerability does not compromise data confidentiality or integrity, the availability impact can indirectly affect business continuity and service delivery. Organizations in sectors with high dependence on mobile remote access, such as finance, healthcare, and government, may face heightened risks. Additionally, disruption of remote access tools during critical periods (e.g., regulatory reporting deadlines or emergency response) could have cascading effects. The fact that exploitation requires no authentication or user interaction increases the threat level, as attackers can launch attacks remotely and at scale without insider access or user involvement.

CWE-426Untrusted Search Path (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product searches for critical resources using an externally-supplied search path that can point to resources that are not under the product's direct control.
Architecture and Design · Implementation · Attack Surface Reduction
Hard-code the search path to a set of known-safe values (such as system directories), or only allow them to be specified by the administrator in a configuration file. Do not allow these settings to be modified by an external party. Be careful to avoid related weaknesses such as CWE-426 and CWE-428.
Implementation
When invoking other programs, specify those programs using fully-qualified pathnames. While this is an effective approach, code that uses fully-qualified pathnames might not be portable to other systems that do not use the same pathnames.
Implementation
Remove or restrict all environment settings before invoking other programs. This includes the PATH environment variable, LD_LIBRARY_PATH, and other settings that identify the location of code libraries, and any application-specific search paths.
OWASP Cheat Sheets
Software Supply Chain Security (opens in a new tab)
Infrastructure as Code (opens in a new tab)
Attack patterns
Leveraging/Manipulating Configuration File Search Paths (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Jul 2025, 07:26 UTC

WeaknessesCWE-426

Technical details

References

Community reviews

Related threats