Security readout for executives and security teams
Plain-English summary
CVE-2021-4339 exposes user names and email addresses from WordPress sites running the uListing plugin through version 1.6.6. The business impact is privacy loss, phishing enablement, and regulatory concern, not direct site takeover based on the supplied sources.
Executive priority
Prioritize remediation for public WordPress sites because the flaw can disclose user email data without credentials. It is not described as remote code execution, but confidentiality impact is high and exposed emails can support targeted fraud or credential attacks.
Technical view
The issue is an authorization bypass caused by a missing capability check in uListing's REST API route /1/api/ulisting-user/search, mapped to CWE-862. CVSS 3.1 is 7.5: network reachable, low complexity, unauthenticated, no user interaction, high confidentiality impact only.
Likely exposure
Exposure is likely limited to WordPress sites with the Directory Listings WordPress plugin - uListing installed at versions up to and including 1.6.6. Public-facing sites are the primary concern. The source bundle's affected-version metadata is sparse, so confirm installed plugin version directly.
Exploitation context
The source bundle does not identify CISA KEV listing or active exploitation. The condition is still practical because the vulnerable route is network-accessible and requires no authentication, but no supplied source proves exploitation in the wild.
Researcher notes
Sources agree on an unauthenticated information disclosure through a missing authorization check in route handling. Evidence is sufficient for vulnerability triage, but the bundle does not provide exploit telemetry, a named fixed version, or detailed patch guidance beyond the referenced WordPress changeset and vendor reporting.
Mitigation direction
- Check whether uListing is installed and identify its exact version.
- Update uListing if running version 1.6.6 or older, following vendor or WordPress plugin guidance.
- Disable or remove the plugin if a safe supported version cannot be confirmed.
- Review access logs for unusual requests to uListing REST API routes.
- Treat exposed user emails as potential phishing targets.
Validation and detection
- Inventory WordPress sites for the uListing plugin and recorded version.
- Confirm vulnerable versions are no longer present in production.
- Verify unauthenticated users cannot retrieve user lists through uListing REST API behavior.
- Review WordPress user accounts for unexpected disclosure-sensitive data.
- Document remediation evidence for privacy and incident-response records.
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-862: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupDatabase behavior lookup
The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-4339 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.wordfence.com/threat-intel/vulnerabilities/id/0a6615fd-7c37-45d9-a657-0ba00df840e5?source=cveCVE reference
- https://blog.nintechnet.com/wordpress-ulisting-plugin-fixed-multiple-critical-vulnerabilities/CVE reference
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2456786%40ulisting&new=2456786%40ulisting&sfp_email=&sfph_mail=CVE 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.
Missing Authorization
Missing Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.