Security readout for executives and security teams
Plain-English summary
ElasticPress for WordPress versions up to 3.5.3 had a CSRF flaw in its autosuggest settings flow. An attacker would need to trick a site administrator into taking an action, such as following a malicious link. The likely business impact is limited unauthorized configuration or parameter submission, not data theft or service disruption.
Executive priority
Treat as a routine but real WordPress hygiene issue. Prioritize patching affected public sites and sites with many administrators, but this is not a crisis-level vulnerability based on the provided evidence.
Technical view
The issue is CWE-352 caused by missing or incorrect nonce validation in epio_send_autosuggest_allowed(). A forged administrator-initiated request could send allowed autosuggest parameters to elasticpress.io. CVSS 3.1 is 4.3: network reachable, low complexity, no privileges, user interaction required, low integrity impact only.
Likely exposure
Exposure is limited to WordPress sites running the ElasticPress plugin at version 3.5.3 or earlier, especially where administrators are actively logged in and can be socially engineered.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. Exploitation depends on administrator interaction, so risk rises with exposed admin users and weak anti-phishing controls.
Researcher notes
The key control failure is nonce validation around epio_send_autosuggest_allowed(). The WordPress Trac changeset is relevant for understanding the fix direction, but the prompt does not provide enough detail to assert exploit maturity or broader impact beyond autosuggest parameter submission.
Mitigation direction
- Upgrade ElasticPress to a vendor-supported version newer than 3.5.3.
- Review vendor and WordPress plugin guidance for the exact fixed release.
- Limit WordPress administrator sessions to trusted devices and networks.
- Train administrators to avoid unexpected plugin-setting links or prompts.
- Monitor plugin configuration changes for unexpected autosuggest-related updates.
Validation and detection
- Inventory WordPress sites for ElasticPress and record installed versions.
- Confirm no production site runs ElasticPress 3.5.3 or earlier.
- Review admin activity logs for unexpected ElasticPress autosuggest configuration changes.
- Verify plugin updates were applied from trusted WordPress or vendor sources.
- Check whether web security controls log suspicious forged admin requests.
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-2021-4405 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/8ab8eb9d-1427-4e99-8986-179147e0862e?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/2473455/elasticpress/trunk/includes/classes/Feature/Autosuggest/Autosuggest.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.