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CVE-2026-19807— ByteCoreStack <= 1.2.3 - Authenticated (Subscriber+) Privilege Escalation via wp_update_user_meta MCP Tool

Quick assessment

Affected
bytecorestack ByteCoreStack – MCP Connector for AI Tools
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

WordPress 插件 ByteCoreStack – MCP Connector for AI Tools 在所有版本（包括 1.2.3 及以下）中存在权限提升漏洞。该漏洞源于 函数中的 MCP 工具仅使用 来限制写入操作。然而，当目标用户 ID 与调用者自身一致时，WordPress 核心的 机制会将此权限检查解析为 （读取）基础权限，而非更严格的编辑权限。同时，该插件对元数据键名（meta key）的黑名单过滤不完整，仅屏蔽了 、 和 ，却未对关键的 （用户能力/角色）和 （用户等级）元数据键进行保护。 这

CVSS 8.8 · High
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I. Basic Information for CVE-2026-19807

Vulnerability Information
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Vulnerability Title
ByteCoreStack <= 1.2.3 - Authenticated (Subscriber+) Privilege Escalation via wp_update_user_meta MCP Tool
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
特权管理不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
bytecorestack ByteCoreStack – MCP Connector for AI Tools 0 ~ 1.2.3 -

II. Public POCs for CVE-2026-19807

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III. Intelligence Information for CVE-2026-19807

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Other References for CVE-2026-19807 (13)

IV. Related Vulnerabilities

Same weakness: CWE-269

V. Comments for CVE-2026-19807

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