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TI-2026-79199 Aliases CVE-2026-111958GHSA-5h77-wc4p-vj34

Authentication bypass in Royal MCP via preview link token

Priority LOW 34CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
High
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-287.

Summary

The Royal MCP WordPress plugin before 1.5.7 does not limit a preview-link token to the single preview it was issued for. Anyone who obtains a valid token is authenticated as the token's owning user, which is an administrator in the default configuration, across the entire REST API without a nonce. This is an improper authentication flaw (CWE-287) that an attacker can use to take over the whole site. A public exploit is linked in the references.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

The Royal MCP WordPress plugin before 1.5.7 does not limit a preview-link token to the single preview it was issued for, so any party that obtains a valid token is authenticated as the token's owning user, an administrator in the default configuration, across the entire REST API with no nonce, leading to full site takeover.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00248 16th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix Fixed Royal MCP (Unknown): 1.5.7

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
UnknownRoyal MCPbefore 1.5.71.5.7Patch availableCNA
  • Royal MCP VendorUnknown Affected before 1.5.7 Fixed in 1.5.7 Patch available CNA

Remediation

Update Royal MCP to version 1.5.7 or later, which fixes the flaw.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Royal MCP (Unknown) Fixed in 1.5.7

Timeline

  1. 2026-10-22 Threatist record created from CVE-2026-111958
  2. 2026-10-22 Alias added: GHSA-5h77-wc4p-vj34
  3. 2026-10-22 CVSS score added · CISA ADP
  4. 2026-10-22 Weakness changed · CISA ADP
  5. 2026-10-22 CISA SSVC decision points changed

References

Exploit 1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences