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Security Bulletin: Langflow is vulnerable to information disclosure due to cross-user MCP tool cache collision and incomplete secret scrubbing on public flows

Security Bulletin


Summary

Langflow contains two authenticated information disclosure vulnerabilities. The MCP Tools component caches discovered tools in a shared process-local cache keyed only by the MCP server display name without including the user, session, flow, or resolved configuration; when two authenticated users on the same backend worker configure MCP servers with the same display name and caching enabled, the second user's flow execution can reuse the first user's cached tool object and client context, potentially returning data from the first user's MCP server. The unauthenticated public flow endpoint scrubs stored secrets from node templates using a heuristic denylist that covers common credential names but omits others including Authentication, X-Session-Id, App-Key, and JWT, causing those values to be returned verbatim to any anonymous caller who knows the public flow identifier along with the flow owner's user identifier.

Vulnerability Details

CVEID:   CVE-2026-19300
DESCRIPTION:   Langflow OSS could allow a remote attacker to obtain sensitive information due to incomplete scrubbing of sensitive credential fields.
CWE:   CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
CVSS Source:   IBM
CVSS Base score:   7.5
CVSS Vector:   (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)

CVEID:   CVE-2026-12763
DESCRIPTION:   Langflow OSS could allow an authenticated attacker to access another user's MCP server context due to improper cache key isolation in the MCP Tools component
CWE:   CWE-306: Missing Authentication for Critical Function
CVSS Source:   IBM
CVSS Base score:   4.2
CVSS Vector:   (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N)

Affected Products and Versions

Affected Product(s)Version(s)
Langflow OSS1.0.0-1.11.2

Remediation/Fixes

IBM strongly recommends addressing the vulnerability now by upgrading Langflow OSS to version 1.11.3

Workarounds and Mitigations

None

Get Notified about Future Security Bulletins

References

Off

Acknowledgement

Change History

28 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:
28 August 2026

Initial Publish date:
28 August 2026

UID

ibm17285642