CVE-2026-19807

ByteCoreStack <= 1.2.3 - Authenticated (Subscriber+) Privilege Escalation via wp_update_user_meta MCP Tool

Published Oct 1, 2026 CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Bytecorestack
Bytecorestack bytecorestack – Mcp Connector For Ai Tools
Wordpress-extensions
Wordpress-extensions bytecorestack
Vendors & Products Bytecorestack
Bytecorestack bytecorestack – Mcp Connector For Ai Tools
Wordpress-extensions
Wordpress-extensions bytecorestack
Type Values Removed Values 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.
Title ByteCoreStack <= 1.2.3 - Authenticated (Subscriber+) Privilege Escalation via wp_update_user_meta MCP Tool
Weaknesses CWE-269
References
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Wordfence
Published
Updated
Oct 3, 2026, 3:42 PM
Reserved
Aug 13, 2026, 9:31 PM
Status
Deferred
Published
Oct 1, 2026, 8:16 AM
Modified
Oct 3, 2026, 4:16 PM