VulnerabilityPublished 5 Mar 2026

CVE-2026-28540: Huawei HarmonyOS · Improper Neutralization of Null Byte or NUL Character

Affects Huawei HarmonyOSSource CVE Database V5

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Not known to be exploited · CVSS 4.0 Medium.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

4.0Medium

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

EPSS: 0.08% 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:N/S:U/C:L/I:N/A:N

Attack Vector: Local
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
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: 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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 5 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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
HuaweiHarmonyOS	Affected =6.0.0 =5.1.0	Fixed in–
Huaweihuawei/harmonyos`pkg:deb/huawei/harmonyos`Other threats	Affected =5.1.0 =6.0.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-28540, organizations should implement strict physical and local access controls to prevent unauthorized users from gaining local access to HarmonyOS devices. Monitoring and restricting Bluetooth usage in sensitive environments can reduce exposure. Huawei should be engaged to provide timely patches or updates addressing the null byte handling flaw; organizations must prioritize applying these patches once available. Developers and security teams should audit Bluetooth protocol implementations for proper input validation and memory boundary checks to prevent similar issues. Employing runtime protections such as memory safety tools or anomaly detection on Bluetooth communications may help detect exploitation attempts. Additionally, educating users about the risks of local device access and enforcing device encryption can further reduce potential data leakage.

Description

Out-of-bounds character read vulnerability in Bluetooth. Impact: Successful exploitation of this vulnerability may affect service confidentiality.

Impact

The primary impact of CVE-2026-28540 is the potential unauthorized disclosure of confidential information from the affected device's Bluetooth service memory. While the vulnerability does not allow modification or disruption of system operations, leaking sensitive data could facilitate further attacks or privacy breaches. Organizations deploying Huawei HarmonyOS devices, especially in environments where local access to devices is possible (e.g., shared workspaces, public areas), face increased risk of data leakage. The limited attack vector reduces the likelihood of widespread remote exploitation, but insider threats or attackers with physical access could leverage this vulnerability. The absence of known exploits currently reduces immediate risk, but the vulnerability could be targeted in the future once exploit techniques mature. Overall, the impact is moderate but significant for confidentiality-sensitive environments.

CWE-158Improper Neutralization of Null Byte or NUL Character (opens in a new tab)
Variant weakness
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component.
Developers should anticipate that null characters or null bytes will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
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.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
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)
OWASP ASVS 4.0.3
V1.5.1 (opens in a new tab)
V5.2.2 (opens in a new tab)
Attack patterns
Embedding NULL Bytes (opens in a new tab)
Postfix, Null Terminate, and Backslash (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Mar 2026, 08:33 UTC

WeaknessesCWE-158

Technical details

References

Community reviews

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