Security readout for executives and security teams
Plain-English summary
CVE-2021-39434 is a default administrator username and password issue in ZKTeco ZKTime versions 10.0 through 11.1.0 on listed builds. A network attacker may be able to access sensitive information without prior authentication if the default account remains usable.
Executive priority
Treat this as a high-priority credential exposure issue for any affected ZKTime deployment. The business risk is unauthorized administrative access and sensitive information exposure. Prioritize internet-reachable or broadly reachable internal instances first.
Technical view
The CVE is classified as CWE-521, weak password requirements/default credentials. CVSS 3.1 is 7.5 high, with network attack vector, low complexity, no privileges, and no user interaction. The scoring indicates confidentiality impact only, not integrity or availability impact.
Likely exposure
Exposure appears limited to ZKTeco ZKTime 10.0 through 11.1.0 builds 20180901, 20190510.1, 20200309.3, 20200930, 20201231, and 20210220. Risk is highest where the application is reachable from untrusted networks and default administrator credentials were not removed or changed.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector indicates the issue is remotely reachable and does not require authentication, but the provided sources do not include exploit maturity, attack activity, or patch availability.
Researcher notes
The record has sparse product metadata: affected vendor/product fields are n/a, and the only named affected product details are in the description. No patch, exploit status, or detailed CNVD content is included in the provided bundle, so validation should stay tied to version/build and credential state.
Mitigation direction
- Inventory ZKTeco ZKTime deployments and identify listed affected versions and builds.
- Remove, disable, or rotate any default administrator credentials.
- Restrict ZKTime access to trusted administrative networks only.
- Review ZKTeco or CNVD guidance for fixed builds or vendor remediation.
- Monitor authentication logs for unexpected administrator account activity.
Validation and detection
- Confirm deployed ZKTime version and build against the affected list.
- Review administrator accounts for default, shared, or unchanged credentials.
- Verify untrusted networks cannot reach the ZKTime administrative interface.
- Check access logs for successful administrator sessions from unusual sources.
- Document remediation status for each discovered ZKTime instance.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-521: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-39434 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.cnvd.org.cn/flaw/show/CNVD-2018-26041CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Weak Password Requirements
Weak Password Requirements represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.