Cross-user flow execution via unscoped UUID lookup
Published Jun 23, 2026 · Updated Jun 23, 2026
Authorization bypass in Langflow OSS before 1.9.1 allows remote authenticated users to execute another user's flow by its UUID. The get_flow_by_id_or_endpoint_name helper directly retrieves a UUID-selected Flow record without comparing its owner to the authenticated user, and the responses endpoint executes the returned flow. A valid API key and the victim's flow UUID are required; successful exploitation returns flow output, exposes data processed by the flow, and consumes the victim's resources.
Summary
What happened
Authorization bypass in Langflow OSS before 1.9.1 allows remote authenticated users to execute another user's flow by its UUID. The get_flow_by_id_or_endpoint_name helper directly retrieves a UUID-selected Flow record without comparing its owner to the authenticated user, and the responses endpoint executes the returned flow. A valid API key and the victim's flow UUID are required; successful exploitation returns flow output, exposes data processed by the flow, and consumes the victim's resources.
The record
- CVE
- CVE-2026-55255
- Published
- Jun 23, 2026
- Updated
- Jun 23, 2026
- Vendor
- OpenBMC Project
- Product
- Langflow OSS
- Classifications
- CWE-639, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 23, 2026CVE publishedPublication date reported by the CVE source.
- Jun 23, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.9.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Upstream authenticated cross-user flow execution PoCproof of concept · demonstrated
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Reported exploitation
- CISA Known Exploited Vulnerabilities catalog entryknown exploited catalog
Technologies
Your stack
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Your stack
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