User Submitted PostsWordPress extension · Plugin Planet
CVE-2023-4779
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe User Submitted Posts plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's [usp_gallery] shortcode in versions up to, and including, 20230811 due to insufficient input sanitization and output escaping on user supplied attributes like 'before'. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe User Submitted Posts WordPress plugin has a stored XSS vulnerability in the [usp_gallery] shortcode. Attackers with contributor-level or higher permissions can inject malicious JavaScript through the 'before' attribute because the plugin fails to properly sanitize user input and escape output when rendering the shortcode. The injected script persists on the page and executes whenever users access the affected page.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
User Submitted PostsWordPress extension
<= 20230811CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Verify the plugin is installedIn WordPress admin, go to Plugins > Installed Plugins and look for 'User Submitted Posts' by Plugin Planet, or check if the /wp-content/plugins/usp/ directory exists on the serverAffected if The plugin is active and its version is 20230811 or earlier
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Check the plugin versionIn WordPress admin, go to Plugins and locate User Submitted Posts. The version number is displayed below the plugin name. Compare it to the affected range: <= 20230811Affected if The installed version is 20230811 or any version number lower than that
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Identify usage of the usp_gallery shortcodeSearch your WordPress database (wp_posts table) or use a plugin to search post content for the string '[usp_gallery' to see where this shortcode is being usedAffected if The [usp_gallery] shortcode is present in any published posts or pages
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Check if the shortcode uses the 'before' attributeExamine the found shortcode instances. Look for patterns like [usp_gallery before="..."] in post content. The vulnerability specifically affects this attributeAffected if The shortcode is used with a 'before' attribute containing arbitrary content
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Verify contributor-level or higher users existIn WordPress admin, go to Users and check for accounts with contributor, author, editor, or administrator roles. These users can exploit the vulnerabilityAffected if There are users with contributor or higher permissions AND the vulnerable shortcode with 'before' attribute is in use
You are affected if the User Submitted Posts plugin is installed with version 20230811 or lower AND the [usp_gallery] shortcode is being used with a 'before' attribute on your site.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpdate the plugin to a version beyond 20230811. Alternatively, add proper sanitization (sanitize_text_field) and output escaping (esc_html/esc_attr) to the 'before' attribute handling in the usp_gallery shortcode callback.
Fix this in User Submitted Posts
Scoped from the published advisory
- Consultation3.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,832.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-4779 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-4779 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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