Security readout for executives and security teams
Plain-English summary
This CVE affects the WordPress Asset CleanUp: Page Speed Booster plugin through version 1.3.8.4. A logged-in administrator could be exposed to reflected cross-site scripting if they interact with a crafted request. Business impact is limited by the high privilege and user-interaction requirements, but compromised admins can affect site trust.
Executive priority
Treat as a scheduled remediation for WordPress properties, not an emergency response item, unless the affected plugin runs on high-value sites or administrator accounts are suspected compromised.
Technical view
CVE-2021-36899 is CWE-79 authenticated reflected XSS in Gabe Livan's Asset CleanUp: Page Speed Booster plugin <= 1.3.8.4. CVSS 3.1 is 4.8, with network access, low complexity, high privileges required, user interaction required, changed scope, and low confidentiality and integrity impact.
Likely exposure
Exposure is limited to WordPress sites running Asset CleanUp: Page Speed Booster version 1.3.8.4 or earlier. The source bundle does not identify affected CPEs or specific vulnerable parameters.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires an authenticated administrator and user interaction, reducing broad automated risk but still mattering for targeted admin compromise.
Researcher notes
Evidence supports authenticated reflected XSS only for admin-level users on plugin versions <= 1.3.8.4. The bundle lacks endpoint-level details, exploit telemetry, and explicit fixed-version text, so validation should avoid assumptions beyond version exposure.
Mitigation direction
- Inventory WordPress sites for Asset CleanUp: Page Speed Booster versions.
- Do not run plugin version 1.3.8.4 or earlier in production.
- Check Patchstack and WordPress plugin guidance for the fixed version.
- Update or remove the plugin where affected versions are present.
- Restrict administrator access to trusted users with MFA enabled.
Validation and detection
- Confirm whether each WordPress site has the affected plugin installed.
- Record the installed plugin version and compare it to <= 1.3.8.4.
- Review vendor changelog before marking remediation complete.
- Review admin activity logs for unusual plugin-page interactions.
- Ask developers to verify output encoding in affected admin views.
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-2021-36899 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://patchstack.com/database/vulnerability/wp-asset-clean-up/wordpress-asset-cleanup-page-speed-booster-plugin-1-3-8-4-authenticated-reflected-cross-site-scripting-xss-vulnerability?_s_id=cveCVE reference
- https://wordpress.org/plugins/wp-asset-clean-up/#developersCVE 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.
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.