CVE-2026-12763Network attack vectorHinoki check available

Cross-user MCP context access via cache collision

Published Sep 14, 2026 · Updated Sep 14, 2026

Improper cache isolation in IBM Langflow OSS 1.0.0 through 1.11.5 allows remote authenticated users to access another user's MCP context. The MCP Tools component keys a shared process-local cache only by server display name, omitting the user, session, flow, and resolved configuration. Exploitation requires caching, matching server names, and both users landing on the same backend worker; reuse can expose data or permit actions through the first user's MCP context.

CVSS severity4.2
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
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Summary

What happened

Improper cache isolation in IBM Langflow OSS 1.0.0 through 1.11.5 allows remote authenticated users to access another user's MCP context. The MCP Tools component keys a shared process-local cache only by server display name, omitting the user, session, flow, and resolved configuration. Exploitation requires caching, matching server names, and both users landing on the same backend worker; reuse can expose data or permit actions through the first user's MCP context.

The record

CVE
CVE-2026-12763
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
IBM
Product
Langflow OSS
Classifications
CWE-306, T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=1.0.0 <=1.11.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

IBM · Langflow OSSversion=1.0.0 <=1.11.5

Published CVSS scores

4.2IBMCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1213Data from Information Repositories

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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