VulnerabilityPublished 13 Aug 2025

CVE-2025-55280: ZKTeco Co WL20 Biometric Attendance System · Cleartext Storage of Sensitive Information

Affects ZKTeco Co WL20 Biometric Attendance SystemSource CVE Database V5

Not known to be exploited · CVSS 5.2 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 4.0 base score

5.2Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N

Attack Vector: Physical
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: High
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

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

Attack Vector: Physical: The attack requires the attacker to physically touch or manipulate the vulnerable system. Physical interaction may be brief (e.g., evil maid attack) or persistent.
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system 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 Vulnerable System 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 Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Aug 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

AI-suggested

European organizations should implement a multi-layered approach to mitigate this vulnerability. First, physical security controls must be strengthened to restrict unauthorized access to biometric attendance devices, including secure mounting, surveillance, and access logging. Second, organizations should monitor for firmware updates or patches from ZKTeco and apply them promptly once available. In the absence of patches, consider isolating the biometric devices on segmented network zones with strict access controls to limit lateral movement if credentials are compromised. Additionally, change Wi-Fi credentials regularly and use strong, unique passwords to reduce the window of opportunity for attackers. Employ network monitoring to detect unusual access patterns or unauthorized devices connecting to the network. Where possible, replace or upgrade devices that store sensitive data in plaintext with models that implement secure storage and encryption. Finally, conduct regular security audits and employee training to raise awareness about the risks of physical device tampering and insider threats.

Description

This vulnerability exists in ZKTeco WL20 due to storage of Wi-Fi credentials, configuration data and system data in plaintext within the device firmware. An attacker with physical access could exploit this vulnerability by extracting the firmware and reverse engineer the binary data to access the plaintext sensitive data stored in the targeted device. Successful exploitation of this vulnerability could allow the attacker to gain unauthorized network access, retrieve and manipulate data on the targeted device.

Impact

For European organizations, especially those deploying ZKTeco WL20 biometric attendance systems, this vulnerability poses a tangible risk to both network security and data integrity. Unauthorized access to Wi-Fi credentials could allow attackers to pivot into corporate networks, potentially accessing sensitive internal resources or launching further attacks. Manipulation of attendance data could disrupt HR processes, payroll, and compliance reporting, leading to operational and reputational damage. Given that biometric systems are often used in secure or regulated environments, the exposure of configuration and system data could also facilitate more sophisticated attacks or unauthorized surveillance. The requirement for physical access somewhat limits remote exploitation but does not eliminate risk in scenarios such as shared office spaces, maintenance activities, or insider threats. The medium severity rating suggests that while the vulnerability is not critical, it is sufficiently serious to warrant prompt attention, especially in sectors with stringent data protection requirements such as finance, healthcare, and government institutions within Europe.

CWE-312Cleartext Storage of Sensitive Information (opens in a new tab)
Base weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product stores sensitive information in cleartext within a resource that might be accessible to another control sphere.
Implementation · System Configuration · Operation
When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to encrypt the data at rest.
Implementation · System Configuration · Operation
In some systems/environments such as cloud, the use of "double encryption" (at both the software and hardware layer) might be required, and the developer might be solely responsible for both layers, instead of shared responsibility with the administrator of the broader system/environment.
OWASP Cheat Sheets
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.6 (opens in a new tab)
V8.2.3 (opens in a new tab)
V8.2.2 (opens in a new tab)
Attack patterns
Retrieve Embedded Sensitive Data (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

cert-in.org.in/s2cMainServlet?pageid=PUBVLNOTES01&VLCODE=CIVN-2025-0172 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 13 Aug 2025, 12:03 UTC

WeaknessesCWE-312

Technical details

References

Community reviews

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