Arbitrary file write via S3 key traversal
Published Jun 21, 2026 · Updated Jun 21, 2026
Path traversal in Flowise S3 Document Loader 3.1.0 through 3.1.2 allows remote authenticated users to write arbitrary local files. S3.ts derives temporary paths from attacker-controlled S3 object keys and writes them without verifying that the resolved target stays within the loader's temporary directory. Exploitation requires control of object keys in a configured S3 source; escaped writes can corrupt application files, while influenced cleanup paths can delete unintended data.
Summary
What happened
Path traversal in Flowise S3 Document Loader 3.1.0 through 3.1.2 allows remote authenticated users to write arbitrary local files. S3.ts derives temporary paths from attacker-controlled S3 object keys and writes them without verifying that the resolved target stays within the loader's temporary directory. Exploitation requires control of object keys in a configured S3 source; escaped writes can corrupt application files, while influenced cleanup paths can delete unintended data.
The record
- CVE
- CVE-2026-12821
- Published
- Jun 21, 2026
- Updated
- Jun 21, 2026
- Vendor
- FlowiseAI
- Product
- Flowise
- Classifications
- CWE-22, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 21, 2026CVE publishedPublication date reported by the CVE source.
- Jun 21, 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=3.1.0
- Affected versionversion=3.1.1
- Affected versionversion=3.1.2
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
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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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