CVE-2026-2987
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 Simple Ajax Chat plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'c' parameter in versions up to, and including, 20260217 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers 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 Simple Ajax Chat WordPress plugin fails to properly sanitize the 'c' parameter during input and escape it during output, allowing unauthenticated attackers to inject persistent malicious JavaScript. This stored XSS payload executes whenever users view pages containing the injected chat content.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/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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Confirm Simple Ajax Chat plugin is installedNavigate to WordPress Admin > Plugins and locate 'Simple Ajax Chat' in the list of installed pluginsAffected if The plugin is not installed or has been removed entirely
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Identify the installed plugin versionIn the WordPress Plugins list, click on the plugin name to view details, or check the 'readme.txt' file in the plugin directory /wp-content/plugins/simple-ajax-chat/ for the 'Version' fieldAffected if The reported version is 20260217 or earlier (e.g., 20260217, 20260115, earlier releases)
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Verify the plugin is activeIn WordPress Admin > Plugins, confirm the 'Simple Ajax Chat' plugin shows as 'Active'Affected if The plugin is active and the version is 20260217 or earlier
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Check for the vulnerable chat parameter handlingInspect the main plugin PHP file (simple-ajax-chat.php or similar) for how the 'c' POST/GET parameter is handled; look for code that processes user input without sanitize_text_field or similar sanitization on input, and without esc_html or esc_attr on outputAffected if The 'c' parameter is processed without proper sanitization (no sanitize_text_field, esc_html, or esc_attr found in the code)
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Confirm chat submission functionality is exposedTest submitting a chat message via the plugin's frontend form (the 'c' parameter contains the message); verify the submitted content is stored and displayed back without escapingAffected if Chat messages can be submitted and displayed without HTML entity encoding applied to the output
A user is affected if the Simple Ajax Chat plugin is active with version 20260217 or earlier, and the chat submission feature (the 'c' parameter) is accessible and returns unescaped content to users.
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 20260217 that implements proper input sanitization (e.g., sanitize_text_field) and output escaping (e.g., esc_html, esc_attr) for the chat parameter.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-2987 — 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-2026-2987 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
- No spam, self-promotion, credentials, or personal data