Authenticated file write via client-name path traversal
Published Jun 24, 2026 · Updated Jun 24, 2026
Path traversal in Jellyfin 10.9.0 through 10.11.9 allows remote authenticated users to write attacker-controlled .log files outside the log directory. The POST /ClientLog/Document endpoint interpolates unsanitized Client and Version authorization-header fields into the filename used to persist uploaded log content. Any authenticated non-admin account can inject ../ sequences into Client; writes are limited to paths accessible to the service user and retain a .log suffix.
Summary
What happened
Path traversal in Jellyfin 10.9.0 through 10.11.9 allows remote authenticated users to write attacker-controlled .log files outside the log directory. The POST /ClientLog/Document endpoint interpolates unsanitized Client and Version authorization-header fields into the filename used to persist uploaded log content. Any authenticated non-admin account can inject ../ sequences into Client; writes are limited to paths accessible to the service user and retain a .log suffix.
The record
- CVE
- CVE-2026-49247
- Published
- Jun 24, 2026
- Updated
- Jun 24, 2026
- Vendor
- Jellyfin
- Product
- Jellyfin
- Classifications
- CWE-22, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 24, 2026CVE publishedPublication date reported by the CVE source.
- Jun 24, 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=>= 10.9.0, < 10.11.10
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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