Security Bulletin
Summary
IBM ContextForge MCP Gateway includes `regex_filter` and `deny_filter` plugins that operators configure as security controls for PII redaction, secret scrubbing, prompt-injection filtering, and forbidden-content blocking. These plugins contain a filter bypass vulnerability ([CVE-PENDING]) where the scanning loops operate only on top-level keys of `payload.args`, allowing an authenticated MCP client to circumvent all configured rules by nesting the payload one level deeper using the standard MCP tool-call structure (the default shape used by OpenAI, Anthropic, and LangChain integrations).
Vulnerability Details
CVEID: CVE-2026-11918
DESCRIPTION: IBM mcp-context-forge could allow an authenticated user to bypass protection mechanisms due to incomplete recursive inspection of nested payload content.
CWE: CWE-184: Incomplete List of Disallowed Inputs
CVSS Source: IBM
CVSS Base score: 5.4
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N)
Affected Products and Versions
| Affected Product(s) | Version(s) |
|
IBM ContextForge MCP Gateway
| <= v1.0.4 |
Remediation/Fixes
IBM strongly recommends addressing the vulnerability now.
| Product(s) | Version(s) number and/or range | Remediation/Fix/Instructions |
| IBM ContextForge MCP Gateway | <=1.0.4 |
v1.0.5 or later See [release notes](https://github.com/IBM/mcp-context-forge/releases/tag/v1.0.5) |
Note: <Component A / B names> are bundled with <Product profile name> to provide <feature / function description>
Workarounds and Mitigations
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
31 Aug 2026: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
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Document Information
Modified date:
31 August 2026
Initial Publish date:
31 August 2026
UID
ibm17285720