Security readout for executives and security teams
Plain-English summary
Opal Estate for WordPress had a CSRF weakness that could let an attacker change which properties are featured. The attacker still needs a site administrator to be tricked into taking an action, such as following a malicious link. The business impact is limited integrity risk, not data theft or outage based on the provided sources.
Executive priority
Treat as a moderate web application integrity issue. It is not currently evidenced as actively exploited, but real estate listings can be business-sensitive. Prioritize sites with public property listings or multiple administrators, and remediate during the next normal WordPress maintenance window.
Technical view
CVE-2021-4387 is CWE-352 in Opal Estate up to and including 1.6.11. Missing or incorrect nonce validation affects opalestate_set_feature_property() and opalestate_remove_feature_property(). A forged request can set or remove featured properties when an administrator is induced to trigger it. CVSS 3.1 is 4.3.
Likely exposure
Exposure is limited to WordPress sites running the Opal Estate plugin at versions up to and including 1.6.11. Sites not using this plugin are not exposed by this CVE. Administrative users are the practical target because successful abuse requires administrator interaction.
Exploitation context
The source bundle does not show known active exploitation, and KEV is false. Exploitation requires social engineering of an administrator and results in unauthorized featured-property changes. No confidentiality or availability impact is stated in the provided CVSS vector.
Researcher notes
The key evidence is the described nonce validation failure in two Opal Estate functions and the WordPress Trac code reference. The source bundle does not provide exploit confirmation or a definitive fixed version, so remediation should be tied to vendor or WordPress plugin repository guidance.
Mitigation direction
- Inventory WordPress sites for Opal Estate plugin usage and version.
- If installed at 1.6.11 or older, check vendor guidance for a fixed release.
- Update or remove the plugin if no supported fixed version is available.
- Warn administrators not to follow unexpected property-management links while remediation is pending.
- Use standard WordPress hardening and admin session controls to reduce CSRF exposure.
Validation and detection
- Confirm each WordPress site’s installed Opal Estate version.
- Flag any instance running version 1.6.11 or older.
- Review recent admin activity for unexpected featured-property changes.
- After remediation, confirm affected feature-property actions require valid nonce checks.
- Track Wordfence, CVE, and vendor references for updated remediation details.
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-352: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. 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 lookupCVE-2021-4387 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
- Medium
- CVSS
- 4.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/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:R/S:U/C:N/I:L/A:N2.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.wordfence.com/threat-intel/vulnerabilities/id/2645899c-2b6b-48bd-8f33-2a837a951c5e?source=cveCVE reference
- https://blog.nintechnet.com/25-wordpress-plugins-vulnerable-to-csrf-attacks/CVE reference
- https://blog.nintechnet.com/more-wordpress-plugins-and-themes-vulnerable-to-csrf-attacks/CVE reference
- https://blog.nintechnet.com/multiple-wordpress-plugins-fixed-csrf-vulnerabilities-part-3/CVE reference
- https://blog.nintechnet.com/multiple-wordpress-plugins-fixed-csrf-vulnerabilities-part-2/CVE reference
- https://blog.nintechnet.com/multiple-wordpress-plugins-fixed-csrf-vulnerabilities-part-1/CVE reference
- https://blog.nintechnet.com/multiple-wordpress-plugins-fixed-csrf-vulnerabilities-part-5/CVE reference
- https://blog.nintechnet.com/multiple-wordpress-plugins-fixed-csrf-vulnerabilities-part-4/CVE reference
- https://plugins.trac.wordpress.org/browser/opal-estate/trunk/inc/ajax-functions.php#L177CVE 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.
Cross-Site Request Forgery (CSRF)
Cross-Site Request Forgery (CSRF) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.