Vulnerability · Published Jun 30, 2026 · Assigned by ibm
CVE-2026-7663Unauthenticated Cross-User MCP Resource Access and Tool Execution via Streamable Transport Authorization Bypass
Critical 9.1
In plain English
A critical-severity security flaw in Langflow OSS from IBM. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities).
Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.5%top 55.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
IBM Langflow OSS 1.0.0 through 1.9.6 could allow unauthenticated attackers to access protected MCP project resources and execute MCP operations due to improper authorization enforcement in the Streamable MCP transport endpoint.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| IBM | Langflow OSS | 1.0.0 – through 1.9.6 |
Weakness: CWE-285 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
References
- https://www.ibm.com/support/pages/node/7277570 vendor-advisory, patch