VulnerabilityPublished 8 Dec 2025

CVE-2025-66331: Huawei HarmonyOS · Download of Code Without Integrity Check

Affects Huawei HarmonyOSSource CVE Database V5

Not known to be exploited · CVSS 3.3 Low.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

3.3Low

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

EPSS: 0.05% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: 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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 8 Dec 2025
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 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

Affected software

Product	Affected	Fixed in
Huawei HarmonyOS	Affected =5.1.0 =5.0.1 =6.0.0	Fixed in–

AI-suggested

To mitigate CVE-2025-66331, European organizations should implement the following specific measures: 1) Restrict local access to devices running HarmonyOS by enforcing strict physical and logical access controls, including multi-factor authentication and endpoint security solutions. 2) Educate users to avoid interacting with suspicious prompts or downloads related to the office service to reduce the risk of exploitation requiring user interaction. 3) Monitor system logs and network activity for unusual behavior or crashes related to the office service that could indicate attempted exploitation. 4) Employ application whitelisting and integrity verification tools where possible to detect unauthorized code modifications or downloads. 5) Coordinate with Huawei for timely updates and patches, and plan for rapid deployment once available. 6) Consider network segmentation to isolate critical HarmonyOS devices and limit the spread of potential DoS impacts. 7) Develop incident response plans that include scenarios involving denial of service on HarmonyOS devices to ensure quick recovery.

Description

Denial of service (DoS) vulnerability in the office service. Impact: Successful exploitation of this vulnerability may affect availability.

Impact

For European organizations, the primary impact of CVE-2025-66331 is the potential disruption of availability in systems running Huawei HarmonyOS office services. This could lead to temporary denial of service conditions affecting productivity and operational continuity, especially in environments relying on HarmonyOS for office-related tasks. Since the vulnerability requires local access and user interaction, the risk is somewhat mitigated in well-controlled environments but remains a concern in scenarios where insider threats or social engineering attacks are possible. The lack of confidentiality or integrity impact reduces the risk of data breaches or unauthorized data modification. However, critical sectors such as government, telecommunications, and enterprises using Huawei devices could experience service interruptions, which might have cascading effects on business operations. The absence of known exploits and patches currently limits immediate risk but also underscores the need for proactive monitoring and mitigation.

CWE-494Download of Code Without Integrity Check (opens in a new tab)
Base weaknessLikelihood of exploit: MediumOWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.
Implementation
Perform proper forward and reverse DNS lookups to detect DNS spoofing.
Architecture and Design · Operation
Encrypt the code with a reliable encryption scheme before transmitting.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
XML Security (opens in a new tab)
Software Supply Chain Security (opens in a new tab)
Infrastructure as Code (opens in a new tab)
OWASP ASVS 4.0.3
V1.14.2 (opens in a new tab)
V10.3.1 (opens in a new tab)
V13.3.2 (opens in a new tab)
Attack patterns
Malicious Software Download (opens in a new tab)
Malicious Software Update (opens in a new tab)
Malicious Automated Software Update via Redirection (opens in a new tab)
Malicious Manual Software Update (opens in a new tab)
Open-Source Library Manipulation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

consumer.huawei.com/en/support/bulletin/2025/12/ (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Dec 2025, 08:44 UTC

WeaknessesCWE-494

Technical details

References

Community reviews

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