Security readout for executives and security teams
Plain-English summary
CVE-2026-3475 affects the WordPress Instant Popup Builder plugin through version 1.1.7. An unauthenticated visitor can cause the site to run unintended registered WordPress shortcodes through crafted email-verification parameters. Business impact depends on what shortcodes are installed; likely impact is content or workflow manipulation rather than full server compromise.
Executive priority
Treat as a timely plugin update and exposure review, not an emergency unless the site has sensitive shortcodes. Prioritize public WordPress sites using this plugin, especially marketing or lead-generation sites with many add-ons.
Technical view
The vulnerable handle_email_verification_page() path builds a shortcode string from GET parameters token and email, then passes it to do_shortcode(). Sanitization with sanitize_text_field() and esc_attr() does not remove square brackets, allowing shortcode parsing to be altered. Missing authorization on the init hook makes the issue reachable without login. CVSS is 5.3, network, low complexity, no privileges or user interaction.
Likely exposure
Internet-facing WordPress sites using Instant Popup Builder versions up to and including 1.1.7 are the relevant exposure. Risk increases where other plugins register sensitive shortcodes that modify content, reveal data, or trigger actions when executed.
Exploitation context
The source bundle does not indicate CISA KEV listing or active exploitation. Exploitation requires a crafted request to a vulnerable plugin path and depends on available registered shortcodes. No exploit code or weaponized details are needed to assess exposure.
Researcher notes
The core issue is authorization failure plus unsafe shortcode construction from GET input. The impact is constrained by the behavior of shortcodes registered in the WordPress environment. The provided affected metadata is inconsistent, but the narrative and Wordfence reference state all versions through 1.1.7.
Mitigation direction
- Inventory WordPress sites for Instant Popup Builder and record installed versions.
- Update the plugin if WordPress.org or the vendor provides a fixed release.
- If no fixed release is available, consider disabling the plugin until vendor guidance is clear.
- Review WordPress.org plugin changeset 3477334 and vendor advisories for remediation status.
- Limit installed plugins and shortcodes that perform sensitive actions without authorization.
Validation and detection
- Confirm whether Instant Popup Builder is installed and active.
- Check whether the version is 1.1.7 or earlier.
- Review web logs for unusual email-verification requests containing shortcode-like bracket characters.
- Confirm the vulnerable function no longer passes user-controlled shortcode text to do_shortcode().
- Document any sensitive registered shortcodes present on affected sites.
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-862: 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 lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-3475 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
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/UI:N/S:U/C:N/I:L/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.wordfence.com/threat-intel/vulnerabilities/id/979962e3-9052-4dc9-94d0-3ec8de3d5460?source=cveCVE reference
- https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1772CVE reference
- https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1772CVE reference
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3477334%40instant-popup-builder&new=3477334%40instant-popup-builder&sfp_email=&sfph_mail=CVE 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.
Missing Authorization
Missing Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.