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CVE-2026-19807

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

8.8 High

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

0.37%Unchanged since Oct 2, 2026
90%50%10%1%

What each source reports

CVE List Score used 8.8

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

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.

Record
CVE-2026-19807
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-269
Updated
2026-11-02
EUVDEUVD-2026-90548 8.8

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.

Record
EUVD-2026-90548
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-qwvr-5fhh-47xh 8.8

The ByteCoreStack – MCP Connector for AI Tools plugin for WordPress is vulnerable to Privilege...

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.

Record
GHSA-qwvr-5fhh-47xh
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-269
Updated
2026-11-02
NVD 8.8

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.

Record
CVE-2026-19807
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-269
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-19807 is a high vulnerability (CVSS 8.8) in Bytecorestack – Mcp Connector For Ai Tools, published October 1, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.37%, the 31st percentile. No source names a fixed version.

References

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