Security readout for executives and security teams
Plain-English summary
This is a stored cross-site scripting issue in the Author Bio Box WordPress plugin through version 3.3.1. It matters mainly where administrator HTML filtering is disabled, such as multisite configurations. An attacker needs administrative access, so business urgency is moderate unless admin accounts are shared, delegated, or compromised.
Executive priority
Treat as a moderate-priority hygiene fix. It is not shown as actively exploited, but stored XSS in a WordPress admin plugin can become serious when administrator accounts are compromised or loosely controlled.
Technical view
CVE-2021-39349 is CWE-79 stored XSS caused by insufficient validation and sanitization of several parameters in the plugin admin code. CVSS 3.1 is 5.5 with high privileges required, low complexity, no user interaction, changed scope, and low confidentiality and integrity impact.
Likely exposure
Exposure is limited to WordPress sites running Author Bio Box up to and including 3.3.1, especially multisite or other deployments where unfiltered_html is disabled for administrators.
Exploitation context
The provided bundle does not show CISA KEV listing or active exploitation. Exploitation requires authenticated administrative access, reducing broad internet-scale risk but increasing concern if admin credentials are compromised or widely delegated.
Researcher notes
Evidence supports an authenticated stored XSS in plugin admin handling, not an unauthenticated public-route flaw. The source bundle names affected versions through 3.3.1 and points to a 3.3.2 code changeset as remediation evidence.
Mitigation direction
- Inventory WordPress sites for Author Bio Box version 3.3.1 or earlier.
- Upgrade to the fixed vendor release; the cited WordPress changeset references version 3.3.2.
- Restrict WordPress administrator access to trusted, MFA-protected accounts.
- Review vendor and plugin guidance before applying compensating controls.
- Remove the plugin if it is unused or cannot be updated.
Validation and detection
- Confirm the installed Author Bio Box version on each WordPress site.
- Check whether the site is multisite or disables unfiltered_html for administrators.
- Verify the plugin code includes the sanitization changes from the 3.3.2 changeset.
- Review recent administrator activity and plugin setting changes for suspicious script content.
- Confirm no untrusted users have administrator-level access.
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-2021-39349 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
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/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:N/S:C/C:L/I:L/A:N2.32.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39349CVE reference · x_refsource_MISC
- https://github.com/BigTiger2020/word-press/blob/main/Author%20Bio%20Box.mdCVE reference · x_refsource_MISC
- https://plugins.trac.wordpress.org/changeset/2613798/author-bio-box/tags/3.3.2/includes/admin/class-author-bio-box-admin.phpCVE 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.