Security readout for executives and security teams
Plain-English summary
This is a stored cross-site scripting issue in a WordPress notification plugin. It requires an authenticated administrator-level attacker, so it is not a simple internet-wide takeover risk. It matters most for multi-user or constrained-admin WordPress environments where administrators should not be able to add unsafe scripts.
Executive priority
Treat as a moderate-priority hygiene issue. Prioritize shared WordPress platforms, multisite environments, and sites with many delegated administrators. It is less urgent than unauthenticated remote compromise, but should not remain unresolved.
Technical view
CVE-2021-39340 affects Notification – Custom Notifications and Alerts for WordPress through 7.2.4. Insufficient validation and sanitization in Settings.php allowed administrative users to store web script through several settings parameters. The CVSS 3.1 score is 4.8, with high privileges required and user interaction required.
Likely exposure
Exposure is limited to WordPress sites running the affected plugin through version 7.2.4, especially multisite deployments or sites where unfiltered_html is disabled for administrators.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. Exploitation requires authenticated administrative access, which lowers broad external risk but still matters for delegated-admin, multisite, or compromised-admin scenarios.
Researcher notes
The public description attributes the issue to insufficient input validation and sanitization in src/classes/Utils/Settings.php. Available evidence supports authenticated stored XSS with high privileges required. The bundle does not provide confirmed exploitation or a named fixed version.
Mitigation direction
- Identify all WordPress sites running the affected Notification plugin.
- Check vendor or Wordfence guidance for a fixed plugin release.
- Upgrade or remove the plugin if affected and no fix is confirmed.
- Limit administrator accounts to trusted users only.
- Use MFA and strong access controls for WordPress administrators.
- Review plugin settings for unexpected script content.
Validation and detection
- Confirm whether the plugin is installed and version is 7.2.4 or earlier.
- Check whether the site is multisite or has unfiltered_html disabled.
- Review administrator accounts with access to plugin settings.
- Inspect relevant notification settings for unexpected script content.
- Verify remediation against vendor or Wordfence advisory 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-79: 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-2021-39340 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
- 4.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/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:H/UI:R/S:C/C:L/I:L/A:N1.72.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.8MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/BigTiger2020/word-press/blob/main/Notification.mdCVE reference · x_refsource_MISC
- https://wordfence.com/vulnerability-advisories/#CVE-2021-39340CVE reference · x_refsource_MISC
- https://plugins.trac.wordpress.org/browser/notification/tags/7.2.4/src/classes/Utils/Settings.php#L167CVE reference · x_refsource_MISC
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.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.