CVE-2026-19807
ByteCoreStack <= 1.2.3 - Authenticated (Subscriber+) Privilege Escalation via wp_update_user_meta MCP Tool
Description
The ByteCoreStack – MCP Connector for AI Tools plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.2.3 This is due to the `wp_update_user_meta` MCP tool in `execute_tool` gating writes solely with `current_user_can('edit_user', $uid)` — a check that WordPress core's `map_meta_cap` resolves to the `read` primitive when the target user ID matches the caller's own — while enforcing an incomplete meta key blocklist that covers only `user_pass`, `user_activation_key`, and `session_tokens`, leaving the `wp_capabilities` and `wp_user_level` meta keys entirely unprotected. This makes it possible for authenticated attackers with Subscriber-level access and above to elevate their privileges to Administrator by issuing a `wp_update_user_meta` call over the MCP JSON-RPC endpoint with `key=wp_capabilities` and an arbitrary role array such as `{'administrator': true}` targeting their own user ID, causing WordPress to load that account as an Administrator on the next request.
INFO
Published Date :
Oct. 1, 2026, 8:16 a.m.
Last Modified :
Oct. 1, 2026, 8:16 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-19807
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update the ByteCoreStack – MCP Connector for AI Tools plugin.
- Apply vendor patches if available.
- Restrict access to the MCP JSON-RPC endpoint.
- Review user capabilities after updates.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-19807.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-19807 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-19807
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-19807 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-19807 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Oct. 01, 2026
Action Type Old Value New Value Added Description The ByteCoreStack – MCP Connector for AI Tools plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.2.3 This is due to the `wp_update_user_meta` MCP tool in `execute_tool` gating writes solely with `current_user_can('edit_user', $uid)` — a check that WordPress core's `map_meta_cap` resolves to the `read` primitive when the target user ID matches the caller's own — while enforcing an incomplete meta key blocklist that covers only `user_pass`, `user_activation_key`, and `session_tokens`, leaving the `wp_capabilities` and `wp_user_level` meta keys entirely unprotected. This makes it possible for authenticated attackers with Subscriber-level access and above to elevate their privileges to Administrator by issuing a `wp_update_user_meta` call over the MCP JSON-RPC endpoint with `key=wp_capabilities` and an arbitrary role array such as `{'administrator': true}` targeting their own user ID, causing WordPress to load that account as an Administrator on the next request. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-269 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/19xxx/CVE-2026-19807.json">CVE-2026-19807</a> Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.1.0/includes/MCP/Server.php#L2042 Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.1.0/includes/MCP/Server.php#L2044 Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.1.0/includes/MCP/Server.php#L2046 Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.1.0/includes/MCP/Server.php#L332 Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.1.0/includes/OAuth/Server.php#L122 Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.2.0/includes/MCP/Server.php#L2042 Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.2.0/includes/MCP/Server.php#L2044 Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.2.0/includes/MCP/Server.php#L2046 Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.2.0/includes/MCP/Server.php#L332 Added Reference https://plugins.trac.wordpress.org/browser/bcs-mcp-manager/tags/1.2.0/includes/OAuth/Server.php#L122 Added Reference https://plugins.trac.wordpress.org/changeset/3711908/bcs-mcp-manager/trunk/includes/MCP/Server.php Added Reference https://plugins.trac.wordpress.org/changeset?reponame=&new=3711909%40bcs-mcp-manager%2Ftags%2F1.2.4&old=3711721%40bcs-mcp-manager%2Ftags%2F1.2.3 Added Reference https://www.wordfence.com/threat-intel/vulnerabilities/id/ac09bf3e-49cf-4f11-92ba-d1fbf6f587d7?source=cve