Security readout for executives and security teams
Plain-English summary
A WordPress event-registration plugin could let an outside attacker cause a logged-in site administrator to opt into notifications by tricking them into clicking or loading a forged request. The business impact appears limited to unwanted configuration or notification-state changes, not data theft or site takeover, based on the provided sources.
Executive priority
Treat this as a routine WordPress plugin hygiene issue unless the plugin is widely deployed on business-critical sites. Prioritize quick inventory and upgrade validation, but it does not appear to justify emergency response without evidence of exploitation or broader impact.
Technical view
CVE-2021-4404 is a CSRF issue in Event Espresso 4 Decaf for WordPress through version 4.10.11. The ajaxHandler() function had missing or incorrect nonce validation. The CVSS 3.1 score is 4.3, with network attack vector, no privileges required, user interaction required, and low integrity impact.
Likely exposure
Exposure is most likely on WordPress sites running Event Espresso 4 Decaf version 4.10.11 or earlier. The provided affected-product metadata is inconsistent, so teams should verify installed plugin slug, version, and vendor advisories directly.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. Exploitation requires social engineering a site administrator into performing an action, such as clicking a link. The described effect is opting into notifications through a forged request.
Researcher notes
The core weakness is CWE-352 CSRF caused by nonce validation problems in ajaxHandler(). The evidence supports low integrity impact and required administrator interaction. The provided bundle does not substantiate confidentiality loss, availability impact, unauthenticated direct state change without admin interaction, or active exploitation.
Mitigation direction
- Inventory WordPress sites for Event Espresso 4 Decaf installations.
- Update beyond version 4.10.11 if vendor guidance confirms the fixed release.
- Review vendor and WordPress plugin changelog guidance before applying production changes.
- Limit administrator browsing from authenticated WordPress sessions where practical.
- Train administrators to avoid unsolicited links while logged into WordPress.
Validation and detection
- Check each WordPress site for the Event Espresso 4 Decaf plugin version.
- Confirm whether ajaxHandler() nonce validation is present in the installed code.
- Review admin activity for unexpected notification opt-in changes.
- Verify no cited source confirms active exploitation before escalating as exploited-in-the-wild.
- Document affected hosts, plugin versions, and remediation status.
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-2021-4404 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/89d3a9da-2496-4f75-ad8f-65629f198fe5?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/changeset/2554360/event-espresso-decaf/trunk/core/domain/services/pue/Stats.phpCVE 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.