Vulnerability in Zkteco Inc. Zkbiosecurity
CVE-2016-20031
ZKTeco ZKBioSecurity 3.0 contains a local authorization bypass vulnerability in visLogin.jsp that allows attackers to authenticate without valid credentials by spoofing localhost requests. Attackers can exploit the EnvironmentUtil.getClientIp() method which treats IPv6 loopback address 0:0:0:0:0:0:0:1 as 127.0.0.1 and authenticates using the IP as username with hardcoded password 123456 to access sensitive information and perform unauthorized actions.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.001 (3.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 3.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000
Affected products
- Zkteco Inc. Zkbiosecurity — versions 3.0.1.0_R_230
Weakness classification (CWE)
References
- Zero Science Lab Disclosure (third-party-advisory)
- CXSecurity (third-party-advisory)
- IBM X-Force Exchange (vdb-entry)
- Packet Storm Security (exploit)
- Reference (exploit)
- VulnCheck Advisory: ZKTeco ZKBioSecurity 3.0 Local Authorization Bypass via visLogin.jsp (third-party-advisory)
Frequently asked questions
- What is CVE-2016-20031?
- CVE-2016-20031 is a medium-severity vulnerability in Zkteco Inc. Zkbiosecurity, classified under Use of Hard-coded Credentials. CVSS score: 5.5/10. Published 2026-03-16.
- How severe is CVE-2016-20031?
- Medium severity. CVSS v3 base score is 5.5 out of 10.