Authenticated file write via unsanitized knowledge-base names
Published Jun 23, 2026 · Updated Jun 23, 2026
Path traversal in Langflow OSS before 1.9.0 allows remote authenticated users to write files through the Knowledge Bases API. The create_knowledge_base function joins the supplied name to a user directory without containment validation, then creates that path and writes embedding_metadata.json and schema.json there. Access to the creation endpoint and filesystem permissions are required; exploitation can overwrite knowledge-base metadata or place those files elsewhere.
Summary
What happened
Path traversal in Langflow OSS before 1.9.0 allows remote authenticated users to write files through the Knowledge Bases API. The create_knowledge_base function joins the supplied name to a user directory without containment validation, then creates that path and writes embedding_metadata.json and schema.json there. Access to the creation endpoint and filesystem permissions are required; exploitation can overwrite knowledge-base metadata or place those files elsewhere.
The record
- CVE
- CVE-2026-42867
- Published
- Jun 23, 2026
- Updated
- Jun 23, 2026
- Vendor
- OpenBMC Project
- Product
- Langflow OSS
- Classifications
- CWE-22, 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?
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- Affected versionversion=< 1.9.0
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
- GHSA-79ph-745m-6wxq path-traversal proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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