Security readout for executives and security teams
Plain-English summary
CVE-2021-34626 affects the WP Upload Restriction WordPress plugin. Authenticated low-level users could delete custom file extensions that administrators added, changing upload policy without proper authorization. The known impact is limited integrity loss, not data theft or server takeover.
Executive priority
Treat as a moderate hygiene issue. It is not described as unauthenticated or actively exploited, but it can let low-privileged users weaken administrator-controlled upload restrictions on affected WordPress sites.
Technical view
The issue is missing access control in the plugin's deleteCustomType function. Versions 2.2.3 and earlier are described as affected. CVSS 3.1 is 4.3 with network access, low privileges, no user interaction, unchanged scope, and low integrity impact.
Likely exposure
Exposure is limited to WordPress sites running WP Upload Restriction 2.2.3 or earlier where untrusted or numerous low-privileged authenticated users exist.
Exploitation context
The provided sources do not report active exploitation, and the CVE is not listed as KEV. Exploitation requires an authenticated low-level user account, so risk depends heavily on account hygiene and plugin deployment.
Researcher notes
The source bundle supports CWE-284, missing access control, in deleteCustomType. The demonstrated impact is deleting administrator-added custom extensions. No source provided a fixed version, patch details, exploit activity, or broader product impact.
Mitigation direction
- Inventory WordPress sites for WP Upload Restriction usage and version.
- Check vendor or Wordfence guidance for a confirmed fixed version or mitigation.
- Prioritize vendor-confirmed update or replacement once identified.
- Review low-privileged WordPress accounts and remove unnecessary access.
- Monitor plugin configuration for unauthorized custom extension deletions.
Validation and detection
- Confirm whether WP Upload Restriction is installed on each WordPress site.
- Record plugin versions and flag 2.2.3 or earlier.
- Review admin-added custom extension settings for unexpected removals.
- Check audit or access logs for plugin activity by non-admin users.
- Verify remediation against vendor-confirmed guidance when available.
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-284: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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-2021-34626 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:L/UI:N/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:L/UI:N/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:L/UI:N/S:U/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.wordfence.com/vulnerability-advisories/#CVE-2021-34626CVE 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 Access Control
Improper Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.